If the rain is torrential, you can lose signal, I've even lost signal using a 1.2M dish, on 23.5E. This summer it's happened a couple of times, and I can spot when it's going to happen,
The sky goes that black, that you have to turn the lights on, when it's daytime, then the rain comes down, in a torrent. Fortunately it doesn't last too long, and you can minimize it by ensuring that your dish is aligned correctly, to give you maximum signal, but in some instances that will not help, My signal has gone down from 100% to zero.
It's even worse in a big snow storm, has the snow sticks on your dish, and LNB, but this has only happened once, that I've noticed, fortunately our weather tends to be quite mild.
You also need to check if your LNB/F Connector is well covered, to stop any water ingress, and the same with your cable, look for signs of cracking, splitting, where water can get in.
