MONTHLY WEATHER SUMMARY

By Mike Anderson
California State Climatologist
California Department of Water Resources, Flood Management Division

January 2007

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January started 2007 with record cold air and dry weather. Winter storms that normally cross the state in January were few and far between with cold stable air as a substitute. Record high temperatures were broken in the beginning of the month. However, an arctic air mass dropped into the state mid-month causing temperatures to drop below freezing yielding record low temperatures and widespread crop damage. The cold weather even brought snow in the Tehachapi Mountains. Temperatures moderated by the end of January with some rain falling in the southern part of the state. Statewide, the National Weather Service Cooperative Network reported an average temperature of 43°F, 2°F below the long-term average. The mean maximum temperature in the state was 55.9°F or 0.3°F below the long-term average. The mean minimum temperature was 31.3°F was 3.8°F below the long-term average. Escondido 2 reported the highest average maximum temperature for the month at 69.9°F. Bodie recorded the lowest average minimum monthly temperature at -2.5°F.

The month started with dry and mild conditions due to a high pressure system over Northern California. Offshore flow and increased fire danger occurred in Southern California as a result of this system. A minor storm system passed over the state in the middle of the first week offering some locations the only precipitation to be had for the month. Following this system, cold air flowed into the Central Valley and Northern California intensifying offshore flow and low humidity levels in Southern California.

Weather during the middle of the month included a strong cold front from Canada that brought an arctic air mass to California. Freezing temperatures were recorded across the State and persisted for some time. Sacramento set a new January record for number of consecutive days with below freezing temperatures with 15 days running from January 6th through the 20th. This broke the old record of 13 days which was set in 1949. Many daily low temperature records were broken across the State during this time.

The end of the month brought more mild weather to the state, including another round of offshore winds and increased fire danger for Southern California. A low pressure system traveling down the coast brought showers to parts of the state and heavier rains to Southern California. For the month, the National Weather Service Cooperative Network showed a statewide average precipitation of 0.70 inches which is 3.15 inches below the long-term average or 23% of average.



Page last updated 3/28/07.