yeah, if possibl;e wait till the clover in about 5-6 inches before spraying
as for rain, its been needed up here
as long as the grass is dry to the touch, you can spray,
its very small particles that land on it and absorb into it pretty fast, as long as its mostly dry, it gets sucked in from the tips into the roots, so even if the ground is wet, as long as grass is dry, you can spray and all will be just fine!