Years with January mean temperatures approaching the 50° F level are likely to be years of poor olive production unless the temperatures in the immediate post-January period are cool enough for flower bud development. Intermediate yields can be expected in years with only moderately low January temperatures and moderate to high temperatures in February and early March. Highest olive yields are most likely when both January and February temperatures are cool. In Tehama County, where in most years the January temperatures are cold enough to favor some flower bud initiation in olives, the temperatures of February and early March are also critical in relation to the number of flowers formed and the ultimate yield.