Half Moon Bay usually has mild weather throughout the year. Under the Köppen climate classification, Half Moon Bay has a cool summer Mediterranean climate (Köppen "Csb"). Hot weather is rare; the average annual days with highs of or higher is only 0.4 days. Cold weather is also rare with an annual average of 2.5 days with lows of or lower. Typical of Northern California, most of the rain falls from November to April. The normal annual precipitation is . Snowfall along the coast in Half Moon Bay has never been measurable; however, snow flurries were observed on December 12, 1972, and February 5, 1976. There is often fog and overcast during the night and morning hours, usually clearing to offshore during the afternoon. Persistent sea breezes help to moderate the climate along the coast; farther from the ocean, in places such as Pilarcitos Creek, days are often warmer and nights cooler than on the coast. For the 37th parallel north, the mild summer temperatures of Half Moon Bay are unmatched across the board. Relatively nearby inland cities see significantly warmer temperatures at the same time. In spite of the low latitude and strong maritime influence, nights remain very cool, even in the summer.