This sounds like you have a metal roof. The like to expand and contract in the evening mostly. I have seen them actually pop the nails out in some areas when the attic temperatures get really hot and the roof is a dark color, like most painted types.
The floor is due to being to dry in the winter when the heat removes any moisture from the wood. You could put some moisture in the air .. but dont overdo it or you end up with bigger problems, Health wise!!
You dont say your region/location or house siding/roofing type, so feedback is limited.
You don't happen to live on a firing range?????