I'm interested in how wind chill and temperature come into play while cycling. If I rode on one day with the temperature at 15°F (-9°C), but the wind chill was 1F (-17°C), how would that relate to a day where the temperature is 10°F (-12°C) or 20°F (-6°C) with the same wind chill?
Ok, let's start with wind chill. The faster the wind, the more chill Wind Chill chart from the National Weather Service Read along the top for the temperature without wind, then down for wind chill at different speeds. So, for example, at 15 degrees Fahrenheit (-9°C) in a 15mph (6.7 m/s) wind, effective temperature is 0 degrees Fahrenheit (-18°C). (chilly!) That chart only works up to 40 degrees F (4°C), but it gives the idea! This Wind chill Calculator allows you to put in any value, and speed of air
Of course, that's if you're standing still. If you're cycling you almost always have a headwind, Here is a link to a page with masses of detailed information about headwinds. The faster you go, the faster the effective windspeed, and the lower the temperature felt. This can be really helpful on a hot summer day, or really chilly in a cold winter!
When cycling you have to take this into account - in the winter, layer up (and find a wind proof jacket if possible.) In the summer, it means that you can actually go up that big hill without totally overheating! I remember one hot day, on a steep incline, I rounded a bend, and came straight into the lee (wind shielded) side of the hill - in seconds I was feeling way too hot, without the cooling breeze.
I think it will help the most to simply having a better understanding of wind chill. A wind chill of 1 is a wind chill of 1, regardless of the air temperature you start with ( Granted, to make matters more complex, there's not really a standard for calculating wind chill ). The wind chill you experience personally while on your bicycle depends entirely on your speed / the wind speed, and your direction vs wind direction, and those variables are typically changing constantly and often on a bicycle. If you are traveling at the same speed and direction as the wind, then you won't experience a wind chill.
If you go for a ride on a particularly windy day, the best thing you can do is bring the appropriate extra clothes you'll need to make yourself warmer or colder.
I live in a very cold, very windy place, and I ride all year. In my experience, wind chill as provided by weather reports is not very useful when biking, because it assumes you're stationary (or walking). It's much more useful to know the temperature and the wind speed and direction, and have some experience to judge what that means to you. If the wind is 15 MPH, but you're going to be traveling directly with it or against it, then the wind chill as quoted by the weather report is not going to mean much, is it?
First of all, dress such that there is a minimum of exposed skin. The wind is far less of a factor when you have a good windproof outer layer, after which you can focus on the air temperature. This winter I tried using a raincoat as my outer layer, and it has been remarkably effective because it completely blocks the wind even though it is not insulating at all. Wear whatever sorts of googles, hats, balaclava, etc. to block the wind but still be able to see and breathe.
Second, wear layers so you can adjust how much insulation you have. With experience, you will just pick the right layers for the ride and weather.
If it's going to be windy (maybe like 20+ MPH, where I live it's almost always at least 10 MPH), I'll think about an extra layer, the warmer gloves, etc. One thing that the wind definitely influences is my choice of eyewear. If it's really windy and/or really cold, I'll wear ski goggles, otherwise maybe I'll just wear sunglasses or nothing. Of course it's easy to just bring such things along no matter what, and use them if necessary.
Wind speed to temp table:
9 km/h 18 km/h 27 km/h 37 km/h 46 km/h 55 km/h 65 km/h 74 km/h 83 km/h -29°C -32°C -43°C -50°C -55°C -58°C -61°C -63°C -64°C -65°C -26°C -29°C -40°C -46°C -51°C -54°C -57°C -59°C -60°C -61°C -23°C -26°C -36°C -42°C -47°C -50°C -53°C -55°C -56°C -56°C -20°C -23°C -32°C -38°C -43°C -46°C -49°C -50°C -51°C -52°C -18°C -20°C -30°C -35°C -39°C -42°C -45°C -46°C -47°C -47°C -15°C -17°C -26°C -31°C -35°C -37°C -40°C -41°C -43°C -43°C -12°C -14°C -22°C -27°C -31°C -34°C -36°C -37°C -38°C -39°C -9°C -11°C -16°C -23°C -27°C -30°C -31°C -32°C -34°C -34°C -7°C -8°C -16°C -20°C -23°C -26°C -28°C -28°C -29°C -30°C -4°C -5°C -12°C -16°C -19°C -21°C -23°C -24°C -25°C -25°C -1°C -2°C -8°C -12°C -15°C -17°C -19°C -20°C -20°C -21°C 2°C 0°C -5°C -8°C -11°C -13°C -14°C -15°C -16°C -17°C 4°C 3°C -3°C -5°C -7°C -9°C -10°C -11°C -11°C -12°C 7°C 6°C 1°C -1°C -3°C -5°C -6°C -6°C -7°C -8°C 10°C 7°C 2°C 1°C -1°C -2°C -3°C -4°C -4°C -5°C
Print it and you will always know what to put on.