Here is what I experienced the last two weeks. Small lake with extremely shallow north end where the bass spawn, deeper south end. Two weeks ago the shallow end had reached 63-64 degrees. Bass were not on beds but I was having a great time pulling in big bass hunkered down NEAR the spawning beds. Then an extreme cold front hit with multiple nights at about 32 degrees. Went out again and water temps had dropped 6-8 degrees in the same location I had been catching. The fish were no where to be found.
I waited a few days for a sunny day (we are still having cold-ish nights). I went out and found the shallow north end spawning area was still at about 57 degrees (5-6 degrees lower than it had been). Had another bass guy flag me down and tell me that he had only caught one bass and we discussed the cold front slamming the water temps. I had no luck in the shallow north end. It should have been warming up with several bright, sunny days but it hadn't warmed enough to get the fish active.
So, I did the exact opposite of what I should be doing on that lake in late April. I went all the way down to the south (deeper) end. Guess what? The surface water temps were still at 62-63 degrees. It takes a LONGER amount of time for the DEEPER end of the lake to warm up, AND the same to COOL DOWN. I started throwing into the thickest bank cover I could find with a 1/2oz jig and then a finesse craw T-rigged on a 3/0 hook and a 1/8 oz tungsten weight. I caught 11 bass in 2 hours.
Historically this little lake would be the dead sea on the south (deep) end at the end of April, but with the screwy weather it became the only active area.
Moral of the long story: After a bad cold front during pre-spawn try where they are supposed to be using what they should be eating. If that doesn't work, look for the deeper water for warmer water.