Wanted to know if any of you have general guidelines you follow, when you decide what to wear, based on the expected high temperatures for the day?

I was thinking about this because as a runner I made up a little chart that I follow so I don't have to guess: i.e., if the weather is 60 and above I run in short sleeves and shorts; if the weather is 40-50 I wear short sleeves but long pants, etc.

I'm in Boston and we've had fairly chilly weather here, but every now and then we get a surprisingly warm day. I never know quite how to dress. Last monday I overdressed and sweated to death. Yesterday I undressed and froze. Today it's sunny and high is around 63. I haven't gone out yet but will be leaving shortly.

I just know it is not yet warm enough for skirts and bare legs!!

So what about you? Do you have a mental guideline you follow? At what temp do you wear skirts and bare legs? When do you go out with no jacket or just a cardigan? Etc.