Why does my bottem bracket creak and squak in the summer, but not winter
 

Hello... any ideas why this happens?

why do my brakes squeak in the morning but not in the evening?

Because the grease has run out.

My drivetrain makes very little noise in the winter.... because I wear a hat and it covers my ears.

Thermal expansion rate differences between metals.

^ That actually is a pretty good explanation. Maybe, if it's really hot and you're using a thinner lube, it could be viscosity differences?

In the summer the grease that is in there is getting thinner from the higher ambient temps so it could allow
the parts to rub a bit more, and the thermal expansion could make the parts fit a bit looser. Do not forget
grease is nothing more than a carrier matrix to carry oil and after a certain time the oil gets depleated and
basically have the base and not much oil especially when it gets hot and the oil gets freed from the base
to lubricate some goes to lower spots that are not contact points, when it cools it kind of sucks the oil back
in a capillary action!!

Not really. I don't think the OP is riding from winter to summer everyday.

Also conveniently forgetting the fact that noise usually does not come from where it sounds like it's coming from. The prevalency of threads like "Help my bike makes ____ noise" should tip you off.

http://sheldonbrown.com/creaks.html

Actually it's a waste of time to even speculate given the amount of information that is presented, which is jack all.

Dang. Might as well shut this forum down . . .:p

I think it is a riddle.
Answer: Because you don't ride it in the winter.