Why do my hibiscus have yellow spots on the leaves?

We're in south florida and just had a cold spell. Could that be it? Or a pest maybe? Thanks for any advice!

Can you post a picture? It's really hard to say what it might be without seeing it. Hibiscus are kind of fussy and their leaves will turn yellow and fall off if you stress them out with things like inconsistent watering--if it's something like that then it's really not a big deal, it'll grow new leaves to replace any it loses. Usually though the whole leaf turns yellow, not just spots (or maybe it starts as spots, but it progresses very quickly to the leaf being almost completely yellow) Cold damage doesn't typically show up as yellow spots so I don't think that's it (although if it's been cold and you've been watering them the way you normally would, they might have a bit too much water and that could do it). Or if it's small yellow dots in a stippled pattern it could be something like spider mites.