There is quite often 1 or 2 kicking around and I am there fairly often but I don't always get much time for meet and greet. You will be welcome to come say hello though but can't guarantee much more conversation than that.
When you are running around on a Sunday with a 100 people all generating heat it gets a bit warm. Although the dark corridors keep slightly cooler than outside in general other than the coldest days you will still get warm. I wear a t-shirt all year round and still end up a sweaty mess.