What bait would you throw on a rainy cool day after the spawn?

plastic worm. Real worms comes out when the soil is wet, and occasionally they'll be washed into the lake/river/pond too

I've heard that spinner baits are good for after the rain but I have personally never caught a single fish on one. After rain I use plastics because that's what I always use. Lipless cranks are good. Something with a little rattle. That is, if the water is mirky. But to each his own.

oh yeah craw does well too

Zen has it it right, throw worms and look for run off area's, that said I would also have a crank or spinner at the ready.

Creature Bait,

I happened to notice the PB in your footnote. An 8-lb 15-oz bass is HUMONGOUS,

but even more impressive to me is your honesty in waiving that one ounce

I could easily suggest 4 or 5 lures, but I have a strong hunch that the best performing lure of the day,

will be something other than what I suggested (just trying to be accurate, not evasive).

Roger

After the spawn they should be cruising, if it's cloudy I'd be throwing a spinnerbait or chatterbait, maybe a topwater.

T-rigged Brush Hogs or Trick worms.

I agree that after the spawn they will be on the move and looking for baby fish. However, I also agree that the rain brings out worms and other terrestials and makes the water murky. So the noise is important so your bait can be found. I would use a shiny rattle trap of medium size or a shiny devils horse. Or maybe combine the suggestions of others and use a Johnson spoon with pork rind tail.