December was wetter, warmer than normal

By Gary Robbins
Originally published January 1, 2011 at 7:26 a.m.,
updated January 1, 2011 at 10:47 a.m.

This won't surprise you: December was wetter than normal in San Diego. But it also was warmer than most Decembers, which seems contradictory. It's not. The week-long storm system that drenched the region just before Christmas drew most of its moisture out of the subtropics. (The system originated about 500 miles southwest of Hawaii.) And the storm that hit a couple of days after the main system was largely made up of residual subtropical moisture. So the storms helped lift temperatures regionally. Lindbergh Field in San Diego ended December with an average monthly temperature of 58.8, which is 1.2 degrees above normal.

Here are some other figures that help tell the story of December.

Rainfall: Lindbergh Field recorded 5.00'', which is 3.69'' above normal. It was the wettest December since 1965, and the ninth wettest since record keeping began downtown in 1850.

Wettest day: Lindbergh got 2.01'' of rain on December 21.

Highest temperature: Lindbergh hit 83 degrees on December 12.

Lowest temperature: The temperature fell to 44 degrees on December 31.

Sky conditions: Seven days were partly cloudy, 9 were cloudy and 5 were clear.

January weather outlook ... Based on the historic database, the weather service says:

January is usually the coldest month of the year in San Diego. The average minimum temperature is 49.7 degrees and the average maximum is 65.8, making the mean temperature 57.8.

The coldest January day on record was January 7, 1913, when the mercury fell to 25 degrees downtown.

The city averages seven days of rain, and January is usually the wettest month of the year, averaging 2.28'' of rain. But amounts vary. Lindbergh recorded 8.06'' in January 1995, and there have been many years in which no rain has fallen during January. The only time snow has ever been recorded in San Diego was Jan. 10, 1949, when "a few snowflakes were observed melting as soon as they reached the ground."

About 72 percent of January days are sunny. The average month has 12 clear days, 8 partly cloudy days and 11 cloudy days.

Complete January outlook from NWS

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