Best time of year?

I got a soaring certificate recently, good for one year. I live in
Houston, so I'm wondering if there's a good time of year, as opposed
to a bad one, to use it? I.e. are there times when the thermals are
better, therefore more fun, etc?

I've never done it before; done some hang-gliding and a lot of
skydiving, so the thought of thermals is not real scary. I'm just
looking for when it's most likely that I'll be able to plan and go,
and have fun.

thanks
Wendy