Terrestrial TV thats correctly set up (and not on the very margins of a coverage area) shouldn't drop out unless there is lightning nearby. Rain and wind should not affect it.
I haven't experienced any dropouts during local storms including lightning storms but as
n-bound au posted, distant (fringe) reception can be affected by severe weather between the transmitter and the receiver (you).
There is another phenonoma which is similar to an mirage in a desert, where heat rising off of the ground 'skews' or blocks signals at or about around sunset time but again, this happens to distant station reception and in my case to one channel 75 miles away.
Some viewers have reported broken signals or loss of reception after lengthy rain storms, and it is possible for the wet earth to become a signal reflector. What happens, is the direct signal arrives at your tuner AND a second signal that has bounced off of the ground arrives a moment later, which confuses the tuner. In some cases, more antenna height will resolve this: others claim tilting an antenna slightly skyward can help.
Although not weather related, I have a third (rare) issue. Locally, seaplanes have a dedicated take-off and landing flight pattern that passes directly through the RF datastream from one station. Whenever we hear a seaplane engine, we count: "three, two, one" and our screen goes black. "One, two, three" and the picture returns.
Jim