From Dave Stocks who edits 'The Buzz' (Gilroy Beekeepers Association Newsletter in California):
Fruit trees need a certain number of hours below 45° to set fruit. The exact number of hours depends on the variety. These hours need to be accumulated between mid-November and February. For example, cherries need about 700-1000 chill hours, depending on variety, to reliably flower and set fruit. As of January 28th, we accumulated 567 hours below 45°. This compares to 881 hours by the same date last year. If anyone is interested in tracking chill hours, you can go to: http://fruitsandnuts.ucdavis.edu/Weather_Services/chilling_accumulation_models/Chill_Calculators/index.cfm
How does this affect our bees? Cherries can probably be called, from the small beekeepers standpoint, a minor food source for bees. But the warmth has also affected the bloom cycles of other, more valuable nectar sources. Now, in January, I have lavender blooming, in fact, it has never gone dormant. At my bee yard in the hills, the buckbrush (Ceanothus cuneatus), is beginning to bloom. Normally I wouldn't expect this until later in February. The buds on Toyon are beginning to swell, and indication that the bloom is not far away. Usually, Toyon won't bloom till June. If we just look at today, this appears to be fantastic. The bees are flying, they're bringing in pollen and building up rapidly.
But all is not sunny (no pun intended). A prolonged cold, wet spring could present problems. Depending on your management philosophies, you may have to begin feeding syrup and pollen patties to maintain the current health of the hive. On the other hand a dry spring, to go along with our zero for January rainfall, could be problematic. So hold on, it's going to get interesting!