When I want to do a longer ride (let's say 3 hours) in rainy weather, what are the best ways to keep dry? I already checked this question, but it does not address long rides and most answers only give information about rain coats and tips for short rides, like commuting.
I want to know what clothes to use on long rides:
Short answer: you won't stay dry. Your best option is to maintain comfortable body temperature.
Longer answer: What to wear depends how cold it is, how hard it's raining, and whether your bike is equipped with fenders. In the Pacific Northwe't, we have a lot of light rain and a moderate temperature band. I keep the fenders on year-round (which makes me stick out a lot when I attend events in eastern Oregon ;-) and assume that I'll get wet one way or another. How I dress depends on the anticipated temperature band:
Above 70 F (21 °C): dress as I would if it were dry, namely wicky polyester jersey & socks, spandex shorts. These things air out pretty quickly. I'm usually working hard enough that staying warm is not a problem.
50 - 70 F (10 - 21 °C): A Merino (non-itchy) wool jersey works very well in this band. It holds water, but it'll keep you warm. If it's especially windy or approaching the lower temperature range, I'll add a layer, wear wool/poly socks, a beanie, and a polyester light fleece set of tights. The main purpose of these is to stay warm, especially if I stop (e.g., to change a flat).
Below 50 F (10 °C), it's cool enough that I'll definitely be wearing tights and a rain jacket. I'll also have the closed-finger gloves. For my feet, I'll cover the shoes with a neoprene bootie.
Shoes: The neoprene booties don't ward off water as much as you'd think they would, but they do keep my feet warm. They go on sale for ~$20 at various places. I've been very tempted to wear sandals and wool socks.
Leg wear - the polyester fleece tights tend to go on sale at Costco for ~$20 in the September timeframe. They're great for this temperature range.
Rain jacket: I have a nice Showers Pass jacket with lots of zippered vents and pockets. I find that I tend to keep the underarm zippers open to regulate heat except when it's really cold. When I get warm enough, I'll roll it up and stuff it in the handlebar bag.
Head beanie: is a polyester, light fleece cap that I picked up at REI (though many other places have them).
At a minimum, for cooler weather, I'd say you need to have at least the jacket part of a "sauna suit" -- a lightweight waterproof jacket. In some situations you will appreciate the pants as well. But, as the name implies, a "sauna suit" is incredibly uncomfortable when exert yourself in it, so it's nice to have something a bit less waterproof (but better breathing) for use in light rain or mist.
But the "sauna suit" is nice to have because it's very light and packs into maybe a 6" diameter ball (or almost any other shape with the same volume).
Otherwise, when you think you may get wet avoid cotton (especially cotton socks). And I very much like Coolmax socks, in part because Coolmax doesn't soak up much water and it maintains its loft and cushion even when wet.
For bike touring, I've had some good luck using a rain cape, a bike specific poncho that sits over your bars and is open on the bottom. It provides a lot of ventilation and keeps a lot of the water off your legs without hot rain pants.
You can pair this with some shoe covers and/or gaiters to keep your lower legs dry (or just wear shorts in hot weather and don't worry about your legs). Typically, you'll also want fenders as well to keep road spray from coming up under the cape.
If the rain is light to moderate and I'm only cycling, I'd tend to choose:
If the rain is heavy and I'm only cycling:
If I'm not only cycling, ie I have to look presentable at the other end, the easiest option is to take a change of clothes (in a waterproof bag). Otherwise it does get tricky.
