Why are there gaps between the boards on my wood floor?

Seasonal expansion and contraction of flooring boards is considered normal. There is more humidity during the summer months and your floor soaks it up causing it to expand. Winter months are usually less humid and the floor dries out resulting in gaps between boards. While considered normal, you can minimize expansion and contraction by keeping the humidity in your home between 35 and 55% by using an air conditioner, humidifier or dehumidifier.