Sacramento Executive Airport has recorded rain 13 out of 19 days this December.
The rainy season didn't get off to a great start with slightly below normal rain for October and November. However, the weather pattern shifted by early December.
The jet stream started to favor more frequent weather systems arriving from the Pacific. Some of these systems had a deep southern tap of moisture arriving from near the Hawaiian Islands. Record rainfall was recorded in many places throughout the state on Dec. 11 because of that system.
December rain level over the past five years shows large accumulation differences. But, a wet December doesn't necessarily mean a good water year or vice versa.
The last rain year (July-June) with above average rainfall was in 2010-2011. December 2010 recorded 5.55 inches of rain. The three years that followed were dry and resulted in exceptional drought conditions for much of the state.
December averages 3.25 inches of rain. As of Dec. 19, Sacramento has already recorded 8.50 inches of rain for the month. Last year, Sacramento only received 0.43 inches of rain. That rain year was one of the driest on record. December 2012 was above average with 6.15 inches, but the Sacramento and San Joaquin valleys ended the rain year with below average rain. December 2011 was another dry month with only 0.27 inches of rain.
These recent weather events have helped take the pressure off of a growing drought situation. Three years of below normal precipitation though have severely depleted our water resources. The weather pattern will need to keep weather systems coming into the state well into the start of 2015.