colder? no no!

I was looking at the weather forecast yesterday and it said rainy and 21° and this morning I looked out the window and it was quite windy, but when I looked down on the people they still seemed to dress very lightly as it was hot like the other days. I got dressed, put on my t-shirt and jeans! Have only been wearing skirts or shorts theese pas suuper hot days. And I was thinking about taking a sweater with me, but I didn't.
I came out and went down the metro, and I finaly understood why people still don't dress warmer, even though it's getting colder. The metro is not at all air-conditioned, and with all the people it's still like a sauna down there! And when I'm going out or going to work, I'm spending about 80% of outdoor in the metro! So here I am stil soaking wet, even though i was looking forward to enjoy the slightly colder weather...