Early morning fishing has been good on the Lower Madison.  Afternoons have been slower with warmer water temperatures and floating weeds.  A hike up into the Beartrap is a good option to avoid the tubers and find a bit cooler water.  Small caddis or mayfly nymphs will get most of the trout with a few eating sculpins or crayfish.  Hoppers have also worked well at times.  Larger trout need some extra time to revive when the water is warm.  Be careful not to overwork or keep them out of water too long.

From Fins and Feathers of Bozeman