The city of San Diego, which is about a two-hour drive south of Los Angeles, is 20 minutes north of the US-Mexico border and has temperatures above 70 degrees over 200 days per year. Most of the rain the city receives comes between December and March, but the average amount is less than two inches per month of precipitation during that time. The average daytime temperature in San Diego from December through March is 66 degrees Fahrenheit, well above the vast majority of most other major cities in the the U.S.
The Inland Empire is a region that encompasses Riverside and San Bernardino counties in Southern California, which are due east and southeast of Los Angeles County. As the name suggests, the Inland Empire is a large area that is a significant distance from California's coastal areas. The region, which consists of more than 27,000 square miles, is home to a range of physical geology, including mountains and desert. In the area's largest city, Riverside, the average daytime maximum temperature is 69 degrees from December through February.
The Imperial Valley is an arid area east of San Diego County and south of the Inland Empire. It's bordered by Mexico to the south and Arizona to the east and is home to just three cities with populations over 10,000 people, the most populous being the county seat, El Centro. Much of the Imperial Valley, experiences sunshine over 350 days a year and receives less than three inches of rain annually. The average high temperature in December and January in El Centro is 70 degrees; the average low during the same months is 41 degrees.
The average daily maximum temperature in Los Angeles from December through February is 66 degrees Fahrenheit, which places it second among California cities, after Riverside at 69 degrees and tied with San Diego. When it comes to the warmest low temperatures during winter, Los Angeles' average is fifth highest in the United States, 49 degrees, which is just below San Diego's normal daily minimum temperature of 50 degrees.
