I found this little tid bit on Wikipedia very interesting!
Snow has been recorded falling on San Diego communities only five times in over
125 years of record-keeping.
Snow flurries were last seen in San Diego on February 15th, 2008, and the last
measurable snowfall to hit various neighborhoods and suburbs around the city
fell on December 13th, 1967. In winter, light snow is common in mountainous
regions of east San Diego County above 3000-4000 feet; one can sometimes see
snow-covered mountains from San Diego.