THE ARTICLE IN SHORT
I always found it very difficult to decide what to wear for running or strength training in the outdoors. Especially in the morning, when you're still warm from your bed and looking out at a cloudy autumn day, it is tempting to throw on an extra layer of clothing. That usually leads to sweating which in turn cools you out even more. So how to dress? I documented my clothing in different temperatures (including rain/snow) and created this cheat sheet, which is hanging in my closet. No matter what, I stick to it and it always feels nice.
I won't let low temperatures or the weather stop me from training outside!
The image below is the drawing I have hanging in my closet. I absolutely one hundred percent trust it. Every time I deviate from the cheat sheet, I either feel too warm and start sweating, or too cold and start freezing. In the beginning it might still feel good with that extra jacket on, but 2.5 km in you wish you had stuck to the damn cheat sheet. By now I rather tend towards the cooler side when in doubt. During longer sessions, sweating will make you loose temperature much faster than wearing a bit less.
This will not be the perfect guideline for everyone. It's great for me but you might be a bit more on the freezing side or you actually never freeze at all. The important thing is to notice when you're comfortable with what you're wearing and then to write it down. Trust me, you will forget about it and there will be doubt, if you don't. Once it is minus degrees outside, you'll second guess yourself. But because you KNOW that it worked perfectly last time, you'll be sure what to wear.
So write it down, trust your own cheat sheet and stick to it no matter what.
One more thing: Don't wear cotton t-shirts when doing sports. The natural fiber can absorb a lot moisture while keeping the warmth on the body, which feels very comfortable throughout the day. However when doing sports the moist cotton t-shirt will stick to your body, making you heat up more quickly while slowly cooling you out over a longer period of time. Go buy a sports shirt with synthetic fibers.