According to the studies I have read, temp. is the PRIMARY factor, but it can be delayed by heavy rains. Once the water temp hits 50 and holds there a few days, it is on! Does not matter about the time of year. Moon phase plays a minimal role. There can be more spawning activity during the full moon, but that does not mean it stops once that phase is over, nor that it will be any stronger during that period. It just means it MAY be better then.