I would say the daylight has more of an effect on the bass more so than water temp. I've observed and participated in talks and research done on this very thing. While there are some smaller/shallower lakes where the bass don't go deep because the bait doesn't go deep and you will find these fish crusing the shallows as earlie as feb.  While bigger bodys of water Lk Wa., Samamish the bait goes deeper and the bass follow.  As days get longer there is more weed growth causing higher a oxigen level and cover for bait which in theory will cause the fish to say shallower unless spooked to deeper water.

Here is an earlier discussion of this topic we had on this forum with some interesting points made:

http://www.westernbassclub.com/cgi-bin/yabb2/YaBB.pl?num=1102912959/0

Since that post I have formed a lot of opinions on the subject and could babble for a long time. Imagine that. Here is a short summary of my opinion, but we should take this up in more detail at a tournament or club meeting some day:

I believe length of day is definitely the main factor driving bass migrations over long periods of time. By that, I mean over a period of one or two months, for example March and April, the days are getting longer and telling bass that it is time to move shallow and think about spawning. But in the short-term, say one to two days, warmer water temperatures, especially in shallow lakes where the temperature changes faster, can cause those fish to move up a little faster then they might have based solely on length of day.

So although length of day is probably the most important factor controlling bass location, water temperature can still play an important role day-to-day during certain periods of the year. I think spring is the most important time these two things interact, because obviously bass can't spawn until the water temperature is correct (hypothetically, they might try if it never warmed up, though).

And then there are a bunch of other crazy things like moon phase that seem to have an effect on fishing, too! But we should keep it simple

Chris