Not all of them are....... which is the problem. Some are in a more organic mix, due for a repot. As for the rain, it is a one time thing, its hot, so cold shouldnt be a issue... that being said, half the city is under a foot of water

I find summer storms are not a problem- they soon dry out, whatever the mix, when the sun comes back.

The worst problem I had was in March 2012 - when we had 8" of water in a morning - the guys had just come out of their winter quarters..

This happened, they just swelled up

But did you water them during that period?

Personally, I would just let them dry out and then go back to my normal watering schedule (which is to water after they dry out, anyway). The ones that are due for a repot, I would repot in a grittier mix.

sld, its not that I dont want to repot them, but most of them are opuntias, are quite large, and annoying to repot. On a side note, id still have to produce a large quantity of gritty soil , and that would take time and effort i dont have right now...

I find that rain never harms my plants unless it is also cold. I don't water at all in summer - our rainy season and my cacti are fine. Opuntia aren't usually problematic

Stefan, I let them dry for a couple of weeks is all. Once June arrives it gets HOT and watering resumed. (Although it is tipping down as I write this !!)

Here is the worse affected one 5 years later.

Opuntias are quite hardy in general and are happy growing in our wet and cold winters outside in the garden soil. Just let them dry out.

Its been raining on my collection for 2 or 3 days now, not to hard. Its spring in the PNW and rain happens. I just fit it into my watering schedule, and move on. The plants need to know about rain.