Set the weather and your session. Running warms you up by about 10 degrees (°C), so the outfit is picked with that in mind.
Dress as if it were +13°C (55°F)
Wind
Rain or snow
Session
We added the 10 degrees that running gives you to the temperature outside.
This is a guide, not a rule. Everyone handles heat differently: some people run in a T-shirt at +5°C, others feel cold in it. Adjust the bottom slider to suit you.