2012: Strong microburst winds from thunderstorms hit south Corona (measured at 88 mph) and Temecula (estimated winds 65 mph).
Residential property suffered damage to fences and trees.
1998: Thunderstorms produced heavy rain in the Rosamond area with 1"-2" of rain reported in less than an hour.
Floodwaters were described as “tire deep” in the town.
Wind gusts were estimated between 50 and 75 mph.
1989: One of the most severe convective outbreaks of record in Southern California began on 8.7 and climaxed on this day.
1971: Each day starting on this day to 8.13 it was 100° F in Palomar Mountain, the highest temperature on record.
This also occurred five other days.
1965: A heavy thunderstorm struck Redlands.
Flash floods went into some homes and businesses in Redlands.
Two youths were rescued after being swept nearly two miles down a storm drain system.
1940: The high temperature at Reno, NV was reported at 105° F.
1937: Petaluma had a high temperature of 102° F.
1933: A heat wave began on 8.10 and ended on 8.13 in the Southern California inland valleys; temperatures topped 110° F for several consecutive days.
1898: Fresno sets an all-time record high of the month of August of 113° F (tied on August 8, 1908).
1891: Thunderstorms above Redlands and Rialto dropped intense rain.
Flash floods in the Zanja drainage crossed a street at ten feet deep.
Some squatters and Indians were drowned and their tents and belongings were washed into Redlands.
Rialto and San Bernardino also reported debris flows.
1873: 1.95" of rain fell in San Diego from a tropical storm on this day and on 8.12. 1.72" fell in Paradise Valley (SE San Diego).
Nearly 3" fell in “Cajon Ranch” (probably El Cajon).
This was called the greatest summer rainfall in history.
The previous daily August rainfall record was 0.31" in 1867.
One foot of water was reported on the ground in Cajon Ranch.
Winds “stiffened up to quite a gale”.
Damage was done to roof tops and trees were felled.
Source: NWS San Francisco/Monterey, Hanford, Reno, & San Diego