As I mentioned last week, there are some, stifling hot, occasions when even the lightest knit baselayers aren’t up to the task. The latest light (100 grams/meter or less) poly baselayers dry fast, but there’s something about the wicking process upon which modern poly shirts depend that just doesn’t get the job done in serious heat. Too much moisture is left against the skin, while at the same time the fabric minimizes any benefit you might get from evaporative cooling. I’ve used poly/cotton dress shirts for quite some time, with a fair degree of success, but after a few days they get nasty and chafe. More seriously, they are one trick critters. In anything other than darn hot weather they’ll be in your pack, which during an extended summer rain interlude can mead you’re hauling around a damp ball of slime until the solar gets cranking again.
Patagonia’s Sun Stretch shirt is a, and perhaps for the moment the, solution to this problem. Made from a 52%/48% nylon/poly woven, the Sun Stretch takes the traditional trekking/fishing/safari shirt and builds it from truly light fabric, namely 76 grams/meter. This light a fabric just can’t absorb much water, which has been a big knock against 100% nylon wovens. The poly percentage also helps with breathability and a pleasant and fairly non-synthetic against the skin feel, the other reason why until now woven shirts have never graced my baselayer closet. Because it’s a woven and not a knit, the fabric doesn’t actively seek to suck moisture off your skin, which paradoxically helps in very hot weather by letting evaporative cooling do its thing. The Sun Stretch is not the ideal tool for cold weather, but when moisture transport and overall mitigation is a major concern, it isn’t too much of a liability, either.
Limitations are few. First, it comes in Patagonia’s “relaxed” fit, which means that to get good sleeve length you’ll need to put up with a overly voluminous torso. I’m fortunate in that I can fit into a small, with only the littlest hint of shoulder tightness, and could thus find one on sale. I can tolerate the slightly short sleeves. My vote would be for more conventional sizing. The second limitation is that the stink factor, while far from terrible, is not what we’ve come to expect in the age of Polygiene. With blazing fast dry times it’d still be a good travel shirt, but it would need frequent sink washings to maintain a good margin of social acceptability, especially in the first world.
Detailing and construction quality is typical Patagonia, which is to say quite good. The chest pockets are capacious, the zippers both smooth running and small enough in coil to be unobtrusive. The buttons are sewn on, but plenty thick and feel well attached. Little details, like shoulder articulation and buttons to hold up the sleeves, are all present. I wouldn’t mind a stiffer collar that would stand up for sun protection, but that’s a small issue.
Fit and nitpicks aside I could happily have this and the Sitka Core hoody as my only next to skin layers, year round. The Sun Stretch is particularly nice in that it can work backpacking or mountain biking, and transfer to a rural burger joint without too thoroughly screaming; I’m a “technical” yuppie goon. Taken together the Sun Stretch and Core hoody over 200 dollars worth of shirt, but if you’re going for quality and longevity over quantity, they’d be my suggestion.