2015: A funnel cloud was reported near San Bernardino.
2001: A heat wave started on this day and ended on 5.9. Temperatures hit 109° F at Palm Springs, Thermal, and Borrego Springs, 103° F at Hemet, and 102° F at San Bernardino.
1977: Cloverdale had a low temperature of 35° F.
1976: 1.11" of rain fell in Palm Springs, the greatest daily amount on record for May.
1971: The Padres' home game against the Cincinnati Reds was rained out at (then) San Diego Stadium.
The rainout was the second this season.
1965: Late season cold snap sent the temperature in Fresno plunging to 36° in May, the lowest on record (also tied on May 5, 1975).
1964: It was 36° F in Palm Springs, the lowest temperature on record for May.
1964: It was 15° F overnight at White Mountain, CA (Mono Co.), establishing a then-new U.S. record low for May.
1950: The morning low temperature at Glenbrook, NV, (east shore Lake Tahoe) was 16° F.
Source: NWS San Francisco/Monterey, Hanford, Reno, & San Diego