When was the last time San Diego County had a hurricane?

Hurricane Hilary, a powerful Category 4 storm, is set to make historic landfall this weekend. While you're busy getting sandbags ready, keeping your pets safe indoors, and securing loose items, you might be wondering, when was the last time a storm of this magnitude hit Southern California? According to the National Weather Service, the last time a hurricane

came through Southern California was 165 years ago - the San Diego Hurricane of October 2nd, 1858. That historic storm grounded ships and battered San Diego County with 75 mph winds for several hours.

Storms of this nature are exceedingly rare in this area; it's been 84 years since San Diego County experienced even the slightly lesser threat of a tropical storm. The National Weather Service reported that the last and only known tropical storm to hit San Diego County occurred in 1939, and resulted in $2 million worth of damages (~$43 million in today's dollars.).

According to the National Oceanic and Atmospheric Administration (NOAA), the difference between a hurricane and a tropical storm is wind speed, with a hurricane being any

storm with winds above 74 mph and a tropical storm having wind speeds between 33mph and 73 mph.

One of the reasons that hurricanes and tropical storms have been so unlikely to affect Southern Californians is the cool water temperatures along the Pacific Coast. The National

Weather Service states that "Water temps need to be at least 80 degrees for hurricanes to sustain themselves." The water temperature in California varies between 55 degrees and 75 degrees,

according to Orange County Lifeguards. This means that hurricanes are usually calmed before making landfall in SoCal. Hurricane Hillary has been intermittently downgraded to a tropical storm, or Category 3, as it reaches cooler waters outside of Mexico. The NOAA measured the water temperature off San Diego Bay at 71.8 degrees early this morning - which could help keep the storm at a Category 3 as it makes landfall.