Another reinforcing shot of cool, dry air arrived from the north during the 22nd and persisted for the next five days. This was a similar pattern to what occurred early in the month. Low temperatures reached the 20s in many locations in the San Joaquin Valley, and low- to mid-20s occurred once again in Hanford and Lemoore during Christmas weekend and into the next couple of days after Christmas Day. Some locations in the Kern County desert experienced minimum temperatures in the lower teens during the period. Fog development was generally limited and localized during this time due to a lack of surface moisture.
Bakersfield had a low of 28 degrees on 4 consecutive days (December 24th-27th), tying the coldest day of the month. Yet the high at Bakersfield on Christmas Day was 64, and reached 65 the next day for the warmest day of the month. This was a diurnal swing of 37 degrees for December 26th.
By the 28th, temperatures began to moderate so that nighttime lows were milder until the end of the month. More lower-level moisture moved in from the coast and also contributed to the moderation of the airmass over the San Joaquin Valley. In addition, high clouds moved over the area as weak upper level impulses moved over the region. The upper-level ridge set up over the area on the 30th, allowing the return of San Joaquin Valley fog by the morning of the 31st.
December was a very dry month for much of the forecast area. Little or no snow fell in the Sierra Nevada or any of the mountain areas, and no measureable rain fell in either Fresno or Bakersfield. Fresno had no precipitation measured during this month, while Bakersfield had a trace of rain on the 12th and 13th. Fresno tied December 1989 for the driest December on record; Bakersfield tied for third driest (5 other Decembers since record keeping began in 1887 have recorded a trace, while two had no rainfall). High pressure was persistent along the coast of California for much of the month, and storm systems generally traversed over the Pacific Northwest.
Cooler than average temperatures were realized throughout the region, especially in terms of daily minimum temperatures. Fog development was generally limited over the San Joaquin Valley, so daytime high temperatures reached above average. However, plenty of cooling took place during many of the nights due to generally clear skies, so low temperatures were well below normal for the month. Bakersfield was around 2 degrees below the monthly average temperature, while Fresno was just shy of 1 degree below the average. In summary, this month was cooler and much drier than average.

Frost/Freeze in W CENTRAL S.J. VALLEY, CALIFORNIA
From 24-DEC-11 00:00:00 to 28-DEC-11 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Frost/Freeze in E CENTRAL S.J. VALLEY, CALIFORNIA
From 24-DEC-11 00:00:00 to 28-DEC-11 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Frost/Freeze in SW S.J. VALLEY, CALIFORNIA
From 24-DEC-11 00:00:00 to 28-DEC-11 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Frost/Freeze in SE S.J. VALLEY, CALIFORNIA
From 24-DEC-11 00:00:00 to 28-DEC-11 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet