wait... if you throw seed and it rains downpours... wouldn't that wash the seed away? wouldn't you want to wait till the rains are done, THEN spread the seed?
In a general sense, newly spread grass seed needs to be kept moist for about the first week, so if you can plant before steady rains, mother nature is going to do a lot of your work for you.
Specifically in this case, I got a patching mixture that includes grass seed, fertilizer, and mulch, and it tends to stay where you put it.
Stephen "Blue" Heaslip
Blue's News Publisher, Editor-in-Chief, El Presidente for Life