10 odd facts about San Diego’s weather history — rain, floods, and snow

San Diego skies can shift in an instant (like recently). One moment it’s sunny and mild, the next, storms roll in with heavy rain, wind, or even the rare snowfall. The city’s weather has always been full of surprises — from record floods to scorching heat — and its history proves it’s anything but boring. Here are 10 moments that show San Diego’s wild side.

Charles Hatfield’s Rainmaking Experiment (1915–1916)
In the midst of a severe drought, San Diego hired “moisture accelerator” Charles Hatfield. His chemical towers coincided with massive rainfall in early 1916, ultimately causing devastating flooding. While Hatfield was initially credited with ending the drought, the torrential downpours soon revealed the risks of uncontrolled weather modification.

The Great Flood of 1916
In January 1916, weeks of heavy rain overwhelmed the city’s rivers and reservoirs. The San Diego River overflowed, Mission Valley was inundated, and portions of the Lower Otay and Sweetwater Dams were damaged or failed. Roads, bridges, and rail lines were washed out, homes were flooded, and at least a dozen lives were lost. While the city’s harbor and coastline remained intact, the flood left a lasting impact on infrastructure and prompted decades of improvements in flood control.

Two Big Dam Failures in the 1916 Flood
Lower Otay Dam catastrophically failed, sending a wall of water rushing down the valley. Sweetwater Dam was overtopped and partially destroyed, highlighting the vulnerability of early 20th-century infrastructure.

A Rare Tropical Storm Hits (1939)
September 1939 brought an unusual tropical cyclone near Southern California. The storm dumped heavy rain, caused flooding, and produced strong winds — a rare occurrence for the San Diego region.

Historic Heat Wave, 1963
On Sept. 26, 1963, San Diego recorded its highest temperature ever: 111 degrees F. Fueled by strong offshore high pressure and Santa Ana winds, this record-setting heat wave tested the limits of residents and infrastructure alike.

El Niño’s Big Impact: 1965–66
The 1965–66 El Niño brought unusually heavy rain, including one of the wettest Novembers and early winters on record. The persistent storms affected infrastructure, agriculture, and daily life, highlighting the far-reaching effects of these cyclical weather patterns.

Rare Snowfall in San Diego
Snow is extremely rare in San Diego, but it has occurred on a few occasions: January 1882, January 1949, and December 1967, with nearby areas sometimes recording several inches. These events delighted locals and left a memorable mark on the city.

Tropical Remnants Bring Summer Flooding, 1978
The remnants of Hurricane Norman in September 1978 caused flash floods, mudslides, and rough surf in San Diego County. Even without a direct landfall, the storm left a significant mark on local communities.

Record January Rain, 1979
Jan. 30–31, 1979, brought 2.57 inches of rain in just 24 hours — the wettest January day recorded at the time. Streets and rivers swelled as residents contended with the sudden deluge.

Thunderstorms Are Rare but Happen
San Diego averages only about three thunderstorms per year, and some years see none. When they do occur, these storms can produce dramatic skies, lightning, and brief heavy rainfall, reminding locals that even sunny Southern California isn’t immune to volatile weather.

Sources / Further Reading:

• San Diego History Center, “Hatfield the Rainmaker”
• SunnyCV.com, “The Great Flood”
• Wikipedia, “Great Flood of 1862”
• Wikipedia, “1939 California Tropical Storm”
• 10News, “Timeline: The Few Times Snow Has Fallen in San Diego”
• NOAA / Western Regional Climate Center, “Historic Weather Events”
• Wikipedia, “Hurricane Norman (1978)”
• Climatestations.com, San Diego climate history
• San Diego Digital Archives, 1916 Flood: Old Town Bridge
• San Diego Digital Archives, Flood Lesson Plans: Community Flood Lessons