Maybe you didn’t know they did, but they do; at least, many of them do.  It is perfectly understandable that people are going to take a vacation, go to family reunions, etc., but it seems like many people just don’t give their church attendance a very high place of priority in the summer.  I wish they would, because church needs them, and they need church.  Maybe the Lord had summer in mind when He inspired Hebrews 10:25.