I don't know how it was in Houston this year, but here in the DFW area, we had the mildest summer ever. I had one week where I worked something like 54 hours, but most of the rest of the summer I was barely getting over 40 hours a week. I'm guaranteed a minimum of 30 hours pay a week, so the slow season doesn't hurt me much.
39k doesn't sound to bad at all. My W2 has $41,699 on it that Uncle Sam knows about, and I have 12 years of residential and light commercial experience, 9 of it service.