Sun Hoodie Attributes

The following attributes are noted as being of primary, secondary, or tertiary importance to the overall performance evaluation of a sun hoodie. A few non-important attributes are also discussed, though they do not directly impact our evaluation process.

Air Permeability/Breathability

Air permeability is a characteristic of primary importance. It is a highly desirable feature in garments intended for use in warm sunny weather. It allows warm moist air to escape once generated, and contributes to making the wearer feel cooler. For sun hoodies, more breathability is almost always better, unless considering models designed for use in cold weather or strong wind.

The limiting factor on breathability is UV protection. What makes a garment more or less breathable is the openness or tightness of its knit/weave. Higher breathability is correlated with more open fabrics because more air can pass through. But more open fabrics allow more UV passage, and thus score lower UPF ratings. Sun hoodies with high UPF ratings are made with more tightly knit or woven fabrics, and are measurably less breathable, allowing less air passage.

Because of this, we tend to prefer models in the UPF 15-30 range, which are almost always more breathable than those rated UPF 50+, while still offering sufficient UV protection 99% of the time.

Conducting the wind pass through test

How we tested for breathability: Without access to a moisture vapor transmission rate (MVTR) measuring device, which is designed to measure rain gear breathability and may or may not even work on something as breathable as a sun hoodie, we had to create our own system. We call it the “wind pass through test,” and it is conducted as follows: (1) Place a strong fan blowing directly at an anemometer (a wind speed measuring device), and adjust settings until it holds a steady state in the 13-14 mph range. Drape a single layer of sun hoodie fabric from the torso of a hoodie (a seamless section) directly over the front of the anemometer, and pull it flush and taut over the face of the anemometer but without stretching it. In doing so, all air passing through the anemometer is first passing through one layer of sun hoodie fabric. Allow the anemometer to adjust to the reduced wind speed, and take down the new measurement. In our testing the most breathability sun hoodies reduced wind speed from 13-14 mph to 2.8 mph, while the least breathable models came in below the 0.7 mph measurable threshold of the anemometer device. The mean and median wind pass through test scores were both 1.5 mph.

While the wind pass through test is imperfect and not testing for true on-body breathability (warm air passing from the inside to the outside), both involve air moving through the garment. The wind pass through test allows for empirical measurement, while subjective perceptions of on-body breathability do not. This gives us the ability to rank sun hoodies relative to one another and make qualified inferences about true on-body breathability. Anecdotally, the models that scored higher on the wind pass through test feel perceivably more breathable to the wearer, but we do acknowledge a confirmatory bias in that assessment.

Heat Escape

This is a characteristic of primary importance. With limited exception, sun hoodies are designed to be worn in warm sunny weather, and their ability to keep you cool is of greater importance than their ability to keep you warm (you have other layers for that purpose). While many factors contribute to heat escape, the unifying factor seems to be a thickness and fuzziness. The thicker the fabric, the warmer the sun hoodie will feel and the slower heat will pass through it conductively. The thinner it is, the cooler it will feel. In general, thicker garments are almost always warmer than thinner ones. As such, we tend to prefer thinner sun hoodies in warm-to-hot weather, and thicker sun hoodies in cool-to-moderate weather. Wool yarns usually need to be thicker than polyester yarns to achieve similar durability and UPF ratings, and are inherently fuzzier (fuzz traps dead air), and thus wool sun hoodies tend to feel warmer than polyester.

Measuring 16 layers of fabric for thickness

How we tested for heat escape V1: Because the best way to predict insulativeness is thickness, that is exactly what we measured for. Our measurements were taken with a digital caliper, accurate to within 0.1mm. We measured two layers of torso fabric, folded over eight times for 16 total layers, making sure to minimize wrinkles and avoid seams, and finally draping it over the lower arm of the caliper before cranking it flush with the top but without squeezing. Using this measurement technique, the mean thickness was 8.8mm, and the median was 9.4mm. The thinnest sun measured at 4.1mm, while the thickest was 12.3mm.

How tested for heat escape V2: Acknowledging that thickness is merely correlated to heat retention/escape, we wanted to do better. So, using a thermal imaging camera + thermometer setup, we placed sun hoodies on top of a preheated oven to measure how hot the exterior layer of fabric would get after 30 seconds. The warmest models came in around 85F, while heat immediately passed through the thinnest/coolest sun hoodies which measured in at a record 105F after 30 seconds.

Quick Drying

Quick Drying is a characteristic of primary importance. For most intents and purposes, the quicker the drying, the better. It just makes life so much more pleasant and comfortable when your clothes are dry, and in cooler weather, wet clothing can even be a safety concern. Fabrics that dry quickly are preferable to those that do not. That said, all fabrics dry eventually, and we don’t value drying speed quite as highly as breathability and non-insulativeness, which combine to keep the wearer cool, prevent sweat, and prevent having to dry off sweat as much in the first place.

Pure polyesters and nylons are always the fastest drying, followed by wools, followed by poly/nylon-Spandex blends, distantly followed by plant-based fabrics (Tencel, Modal, etc).

Another important correlation with dry time is thinness and lightweightness. The thinner and lighter the garment, the less water it is capable of holding, and the faster it will dry. Thicker heavier garments are strongly correlated with slower dry times.

Measuring drying speed

How we measured dry time: After trying a few different dry time test methodologies, we settled on the following: run the batch of sun hoodies through a rinse and spin cycle in the washing machine. The hoodies will come out completely wet but not oversaturated. Then hang dry them in the shade (cannot be placed in sun, or color variance will muddy the results). We determined a sun hoodie to be dry if the armpit area was dry with a cursory hand feel. Note the time it took to dry, and adjust time to account for the fact that the first sun hoodies hung up got a head start. Adjust placement of sun hoodies so each gets time in the front row.

Dry time is highly dependent on environmental conditions such as humidity, wind, and temperature, thus no hoodie can have an exact dry time prescribed to it. Our data set speaks to the time it took to dry on a day that ranged from 70-80F over the course of the testing period, with high humidity. But across various versions of this test (measuring from fully saturated, measuring in full sun, etc.), the same patterns always played out, with the same thin poly/nylon hoodies drying first (always the Outdoor Research Echo), and the plant based fabrics drying last. In challenging conditions, for example cold damp air, the delta between fast and slow drying fabrics grew even larger.

UPF Rating

UPF Rating is a characteristic of primary importance. It goes without saying that ultraviolet protection is the name of the game for sun hoodies. It’s their primary purpose. We have a strong preference for UPF rated models over unrated ones, and ding unrated models accordingly when evaluating for potential recommendations.

UPF rating works as follows: the number in the rating, for example UPF 30, means that one in thirty ultraviolet rays pass through the garment to hit your skin. For UPF 15, that’s one in 15 UV rays, and so on and so forth. The higher the UPF rating, the better the protection. The ratings start at UPF15, and any model scoring less than 15 is considered unrated, even if it would have scored UPF10 or even UPF14. As a baseline, all fabric blocks some amount of UV. A white cotton tee shirt blocks one in five ultraviolet rays, and would score UPF 5 on the scale, but no rating under 15 qualifies.

Denser fabrics, synthetic fabrics (nylon/polyester), and darker fabrics tend to score higher UPF ratings, while thin, natural fibers in lighter colors score lower UPF ratings. The delta between black and white fabrics is stark. For one brand, their black and navy blue merino hoodies scored UPF25, while the light heathered gray merino hoodie (same fabric, different dye) blocked 1 in 14.9 rays, would have scored UPF 14.9, but came in below the UPF15 threshold and did not qualify for a rating. We speculate that the difference in color performance is because UV is absorbed into darker fabrics, while lighter fibers will reflect glancing UV ray strikes through their knit structure.

We rely on brand-provided UPF rating scores and did not independently test. While we prefer to verify, it was not feasible to independently measure UPF ratings and will trust what the brands are saying. However, this is imperfect and brands have been known to overstate. A couple of years ago, Patagonia caught some heat for overrating their Capilene Cool series, claiming it be UPF 50 and later downgrading it an average of UPF34 (depending on color) after outcry from consumer watchdogs.

Why Higher UPF Ratings are Overvalued Across decades of collective sun hoodies use and thousands of trail miles all across the world, we have never once been sunburned through a UPF15 sun hoodie.

Mathematically, scaling higher up the UPF rating system has diminishing returns. UPF 50 protects you from 98% of incoming UV, while UP 15 still protects you from 93%. For more than triple the UPF rating, that 5% increase looks pretty meager.

We’ll take higher UPF ratings if we can get them without a cost. But as we covered in the breathability section above, higher UPF rated garments are always less breathable, and breathability is extremely important for warm weather clothing to reduce the likelihood of heat exhaustion. As such, we prefer sun hoodies at the UPF 15-30 level because they offer adequate protection and superior breathability to those in the UPF 50 class. A UPF 15-30 sun hoodie keeps the body cooler than a UPF 50 hoodie will, while still preventing sunburns.

Virtually the only time we would recommend a UPF 50 model is to people with particularly sensitive skin (i.e. you are very fair, genetic history of skin of cancer, or always choose SPF 70 sunscreen), or to those adventuring in extreme UV conditions, such as the high altitude Peruvian Altiplano desert, or mountaineering in the Himalaya. For 99% of hiking and adventure, UPF 30 is all you need, and even UPF 15 is likely sufficient for most people most of the time.

One potential argument against lower UPF rating sun hoodies, say UPF 15 for example, is that they are protective enough to prevent sun burns, but from a skin cancer perspective, still allow a potentially harmful amount of long term radiation through. Consult your doctor for more about skin cancer prevention.

Stretchiness

Stretchiness is a characteristic of secondary importance. The ability for a fabric to stretch is important to all-day comfort and range of motion while active. Up to a certain point, the more stretch the better. We prefer garments with at least average to above average stretch, and view little-to-no stretch as a definite drawback. However, to achieve high stretch, up from average stretch, a garment usually requires the addition of Spandex, which is attributed with many negative characteristics, including slower dry times, heavier weight, less breathability, and worse smelling. As such, our preference is for 4-way mechanical stretch without the use of Spandex. This means it can be stretched vertically, horizontally, and diagonally, without the addition of Spandex. Less mechanically stretchy fabrics are often only stretchable either horizontally, or vertically, or diagonally, and not all three.

How we assessed stretchiness: We broke out the 27 sun hoodie test group into three sub groups: above average stretch, average stretchy, less than average stretch. In evaluating, we tested each for range of stretch on a similar sized section of fabric, as well as assessing for horizontal, vertical, and diagonal stretch and noting spandex derived vs mechanical stretch.

Weight

Weight is a characteristic of secondary importance. Lighter weight fabrics correlate with faster dry time and less insulation, and are generally preferable. If a fabric is lighter weight, it does not drape as heavily and floats on top of your skin, offering greater aeration. It’s also preferable in the event that you need to carry your sun hoodie, instead of wearing it as a base layer. Carrying a compact five ounce sun hoodies is a lot nicer than a bulky 12 ounce sun hoodie.

How we measured weight: We measured each sun hoodie on a postal scale, rather than relying on brand-reported weights. Nearly every hoodie was a men’s large, though a couple of mediums and XLs snuck in. The off sizes were adjusted up or down by 10% to normalize the data. The mean weight was 7.8 oz, and the median was 7.9 oz. The lightest was 4.1 oz, while the heaviest was 11.4 oz.

Odor Resistance

Odor-Resistance is a characteristic of secondary importance. For backpackers and adventure travelers, the inability to wash clothing mid-trip makes odor-resistance a coveted attribute. The best way to reduce stench is with naturally antimicrobial fibers, such as merino, or other wool/plant derivatives. At a microscopic level, each strand of wool is smooth and difficult for bacteria to cling to. Plastic-derived fabrics, like polyester and nylon, do not have any naturally occurring antibacterial properties, and always smell worse (sometimes permanently), after a big sweaty hike. While antibacterial treatments help with this, it does not equate to the overall odor-resistant properties of wool, which are the best performers in this arena.

How we assessed odor-resistance: Our odor resistance evaluation was not based on sniff testing, rather, we scored each hoodie based on the percent of natural fiber included. Wool and plant-based hoodies scored highest, synthetic fabrics with added spandex scored lowest. Despite the fact that nearly all synthetic fabrics now receive some kind of antimicrobial treatment, wool and plant based fibers are still strongly preferred.

Texture

Fabric texture is a characteristic of secondary importance, but is highly subjective and thus was not scored. A comfortable fabric will feel better against your skin all day long, and improve the wearing experience of the garment.

But what is comfortable to one person may not be comfortable to the next. Before purchasing your next sun hoodie, we recommend diving into your wardrobe or visiting REI Co-op to get a sense for the type of fabrics you prefer. Do you like a merino wool or polyester? Do you like a smooth surface, or something more textural. Some of our staff prefers merino, while others literally cannot stand it.

How we assessed texture: for the sake of objectively evaluating a highly subjective attribute, we attempted various iterations of a hand feel test. The first version involved having testers stack rank all of the sun hoodies from best to worst. Simplifying further, the test subjects were then asked to touch each sun hoodie and place them into one of four tiers based on their initial reaction to the fabric: bad, okay, good, or great. Hypothetically, this would allow us to create an average score for each hoodie.

However, results varied wildly from person to person. To illustrate this, one tester’s two favorites and two least favorites were the next tester’s two least favorites and two favorites, respectively. Without enough sample size to cut through the noise, aggregate hand feel was eliminated as a scoring criteria. Average perceptions of fabric feel are less important than identifying your personal preferences. Most importantly, you should figure out whether or not you prefer merino vs polyester, and smooth vs textured.

Early attempt at stack ranking for hand feel preference

Water Absorption

Water absorption is a characteristic of tertiary importance that is closely correlated with dry time, thickness, and weight. Faster dry times quite accurately predict less water absorption, as do weight and thickness. The more fabric there is, the more water can be held. Though we did measure for it, we did not factor water absorbency into our evaluations because dry time is a more important but very similar trait. Fast wicking garments are also associated with higher water absorption capacity, but because we don’t value wicking highly, we also don’t value absorption highly.

How we assessed water absorption: This was measured by weighing a sun hoodie, dipping it into a bowl of water to complete saturation, allowing it to drip dry for three minutes, placing it into an empty bowl, measuring again, and finally subtracting the weight of the hoodie itself. You’re left with the water weight – how much it has absorbed.

Our findings painted a very clear picture. The three least water absorbent sun hoodies were also the three lightest weight models, and many of the heaviest were also the most absorbent. More than any particular fabric characteristic, what seems to matter most for quick drying performance is minimizing mass.

Weighing a saturated sun hoodie to measure absorption

Moisture Wicking

Moisture Wicking is a characteristic of tertiary importance, the idea that the interior face of the fabric will absorb sweat off your skin and transfer it to the exterior face of the garment where it will then evaporate. Every sun hoodie claims to be, and is, moisture wicking. In fact, all fabric is moisture wicking, though some fabrics, like wool and plant-based fibers, wick faster than synthetics like polyester and nylon.

One of our most-used all time sun hoodies, the 100% polyester Outdoor Research Echo Hoodie, is quite a slow moisture wicker (because it absorbs little water), but we have always found it to be perfectly sufficient regardless. Fast wicking garments exhibit higher water absorption and slower dry times, and tend to be thicker and heavier. As such, we prefer the overall performance characteristics of slower wicking garments, because they tend to dry faster, be thinner, and cooler. How quickly a garment wicks is not very perceptible to the wearer. What matters more is dry time.

In high exertion, high sweat activities, the speed of wicking matters little because the garment will quickly be overwhelmed in sweat. When it comes to moving moisture from on-body to evaporating off the exterior of the garment, a fast wicking slow drying model will be outpaced by a slow wicking fast drying model. No sun hoodie fabric is both fast wicking and quick drying, as increased water absorbency sows dry time. As such, we feel that moisture wicking is a heavily overvalued performance trait, and we don’t place much stock in it.

Fit

Fit is a tertiary characteristic in our analysis because it is 100% relative, though it is likely the single most important factor when it comes to overall comfort. We do not evaluate sun hoodies from this perspective, because all bodies are different, and what might be a perfect fit for someone could be a wretchedly poor fit for another person.

That being said, when it comes to hot-weather wear, we recommend loose fitting clothes. With more air circulating around your skin, the comfier and cooler you will feel. Some sun hoodies are designed with a trim fit in mind (which we disagree with from a design perspective), and for those models, we recommend sizing up such until a relaxed fit is achieved.

Durability

Durability is a characteristic of tertiary importance. To maximize performance as warm weather base layers, sun hoodies are designed to be as thin, soft, lightweight, and breathable as possible. As such, their overall durability is low-to-moderate, and some degree of pilling and snagging is to be expected over the lifespan of the garment. If treated respectfully, even the thinnest sun hoodies last a few seasons of heavy use.

We only consider a sun hoodie to be inadequately durable if it does not hold up to the gradual wear and tear of hiking with a backpack. As a sun hoodie attribute, high durability should not be prioritized, unless you partake in abrasive activities like bushwhacking, canyoneering, or intend to wear it for an entire thru-hike. Increased durability is correlated with denser fabrics, lower breathability, slower dry time, and less pleasant texture. If you want to maximize durability, choose something that is 100% polyester without spandex (stretchy spandex increases snagging potential), and UPF 50 (because UPF 50 is thicker and denser).

Style

Style is a non-performance characteristic, and was not factored into our evaluations directly. While subjective, everyone prefers to have a good looking, properly fitted sun hoodie in a color that compliments them from a brand they admire. Don’t be afraid to factor in your style preferences. If wearing it makes you look good, then you will perceive it to feel and perform better, and it will make your day just a little bit nicer. Sounds good to us! Which is your favorite?

Price

Price is a non-performance characteristic, and was not factored into our evaluations directly. As of summer 2024, the mean price of the 27 featured sun hoodies was $84, and the median was $85. The most expensive was $139, and the least expensive $20. Wool garments tend to be the most expensive, while synthetics are less expensive. We leave you to determine the optimal value-to-performance ratio.

Sustainability

Sustainability is a non-performance characteristic, and was not factored into our evaluations directly. For those prioritizing sustainability, sun hoodies made of natural fibers are the first choice, followed by recycled fibers. Wools are preferable because they circumvent the need for petroleum, and reduce micro-plastic shed. Plant based fibers are arguably the most sustainable, but are agonizingly slow drying, and not recommended for active wear. Recycled polyester and nylon is highly preferable to virgin, because it keeps plastic out of the landfill without any noticeable hit to performance.

Aggregate User Review Data

Aggregate user review data is a non-performance characteristic, and was not factored into our evaluations directly. We often take into account this information. If one model averages 3.7 stars on 100s of reviews, while another averages 4.7 stars on 100s of reviews, that matters, and makes the 4.7 look a whole lot more tempting. However, our audit of the marketplace concluded many new or lesser known models do not have sufficient review sample size from which to pull data, and nearly all of those that do score at least 4.5 stars. At baseline, sun hoodies are incredible garments, and even low performers might be perceived as 5-star worthy to a first-time sun hoodie wearer. What’s more, review scores are frequently manipulated, inflated, or duplicated by brands who are incentivized to sell their products. As such, we chose to exclude user review data from this study.