Seassonally Frustrated

ry-con

I love winter but, when the weather changes so does the gap between my counter backsplash and the wall.In the winter the gap opens,and in the summer it closes tight.The kitchen was installed in the summer.
Also my base-boards do the same,where I have hardwood floors.
The whole house probably does the same but I really notice it where the hardwood floors are.
My house is 2.5 years old.I have lived in 4 new houses and all have done the simular thing.I have measured the base boards and they are not expanding & contracting The gap reaches3/16 annnoying!
My house has a crawlspace in a high water table but it is dry & has air circulation..
I have never had a client comment about this,but I am certain that it must be happening.
Does any body have the answer.