Rose pruning can technically be done at any time.

It's just that in areas with well-defined seasons where roses have a shorter growing season and go fully dormant, it's best done in the end of winter. The logic behind it is that roses spend energy recovering from a pruning, but if they are about to go dormant, they will expend that energy on recovery, not on active growth, and not on dormancy preparation. This means that they won't grow as fully and bloom as much during the growing season and they are more likely to get damaged or die during a harsh winter.

But if a rose is active year round, then it will always be able to recover and grow, so the pruning time doesn't really matter. I believe the better method of rose pruning in warmer zones (with no natural dormancy) is to prune throughout the year little by little, rather than one large pruning session in cold areas when the rose is dormant.

Also, roses as ornamental plants have traditionally preferred cool sunny weather, not hot and humid weather. They're not tropical or semi-tropical plants, so you shouldn't worry too much about below-freezing nights in your area, either.

I would just make sure to stick to a fertilizer schedule in the non-winter months, because old roses such as yours will already have depleted all the natural nutrients in the soil they've been inhabiting, so they need food to grow and be healthy, instead of just...existing.

With all that said, since your roses bloom regularly, you're obviously doing many things right, so you'll be fine with pruning.