In the rain, I look for areas with cover from the rain, near their normal haunts...
I have actually had good luck hunting in the rain, but the birds come in quiet, and you cannot even hear them walking (due to the damp ground). I like to run & gun, but in the rain, I am more likely to commit to a spot, knowing that the birds will not be as vocal...
If you are in a good turkey local, and can stay fairly dry yourself (due to the cover), you are probably in a good spot...