That would depend on water quality at the surface and the presence of the bait near the surface but as Boatman Bill said, the low 70's typically. In the spring, they typically get going on the surface somewhere between 55 and 65 degrees and in the fall there's usually a pretty decent morning and evening top water bite by the time it hits 65. I haven't seen much yet but maybe this weather will bring a change in the top water scene??
We saw lots of bait on the surface this afternoon as the sun was going down. Shad spawning during this full moon. It was everywhere from young deer to the Horseshoe. Did manage to catch a few stripes on spoons biggest was 15lb.
We fished off the dock yesterday evening and for about an hour or two before dark several bait pods out in our bay were under attack by a few little buck bass on the surface. It was like the water show at Bellagio's in Vegas. The whole bait pod would skitter across the surface in a wave to elude the bass attack. The bass would come from different directions and send the bait across the surface in a shimmering wave of panic. Some of the bigger bait pods were 10-20 feet across so when they moved it was a pretty big display. We watched this happen over and over again last night with several bait pods and I gotta tell ya, as a fisherman watching that scene never gets old. Next time it happens we'll have the yaks ready to go.
I threw the net on one of the pods last week and the bait pods were mainly threadfins of various sizes.