I have to keep track of temperature and what to wear at different temperatures. The last thing you want to to miss the mark and have to deal with a long run in misery.
This morning, 43° 8 mile run, 6-7 am darkness, lets go with cotton socks, tights ,performance tee to wick away the sweat, long sleeve thermal shirt (Costco Heat Guard or something like that) Pearl Izumi light weight cycling jacket, North Face wool hat, cycling gloves with fingers (getting obvious I'm a triathlete) I put on a headlight, really tight. I prefer squeezing my skull to having that thing bouncing around up there. Then the led vest light. Looks like air traffic control.
The run started out unusually great. my breath is visible due to the LED light on my head lightening up the steam. Temperature is perfect. My run starts up a nice hill and gets my heart rate up fast. Then down hill to get some speed. Unzip my jacket, get some air into my chest.
A few miles in, I am warm. My hat can come off and my gloves are starting to get damp. Jacket is halfway unzipped. I decide to take off my headlight in a very dark upscale residential neighborhood. I run hills by the starlight and zone out. A few house lights are on, but this area, houses are built on a few acres minimum, so its a nice dark stretch.
I'm holding my hat and my headlight in my hand. I have already put my gloves into the back pocket of my jacket. Next run at 43°, I might wear the same thing. Can't deal with the sting of the cold first thing. Taking off the hat and gloves mid run was not too big of an issue.
Best run in a long time.