When will heavy rain hit Southern California and how long will it last?

People walk, jog and ride bikes on a beach path in front of a lifeguard tower on an overcast day.
Rain yields to gray skies and low clouds along Granada Beach on a dry but overcast day in Long Beach.
(Brian van der Brug / Los Angeles Times)

Rain is beginning to hit Southern California as another atmospheric river storm moves through the state. Here is what to expect:


  • Tuesday: Rain was falling in San Luis Obispo County on Tuesday morning and was expected to strengthen as the storm moves south through the day. The storm’s worst is expected in Santa Barbara and Ventura counties on Tuesday afternoon and evening, and in Los Angeles later Tuesday night.
  • Coastal and valley areas could see 2 to 5 inches of rain, with Santa Barbara County hit hardest. Strong winds are also expected, especially in mountains and passes.
  • There are threats of mud and debris flows in steep terrain and around wildfire burn scars — including those of the Alisal, Cave and Thomas fires, where Santa Barbara County officials have issued a mandatory evacuation order.
  • Wednesday: Rainfall will strengthen along the coasts and in the valleys of Orange County, the Inland Empire, and the mountains of San Bernardino, Riverside and San Diego counties after midnight Wednesday and will last until about noon.
  • Rain is expected to taper into showers in most of Southern California by Wednesday afternoon, and move out of the area by the end of the night.
  • Thursday-Saturday: Mostly cloudy.
  • Sunday: Chance of scattered rain overnight and into morning.


  • The Ventura, Sisquoc and Santa Ynez rivers may get close to flood stage, and smaller creeks and streams are expected to fill.
  • Flood watches are in effect in San Luis Obispo, Santa Barbara, Ventura and Los Angeles counties through Wednesday morning. “The threat for significant roadway flooding and small creek flooding is high, so we would expect a lot of significant road delays and even some closures,” said Ryan Kittell, a meteorologist with the National Weather Service in Oxnard.
  • The San Gabriel and Los Angeles rivers “will definitely have a lot of flow, and that usually will result in swift-water rescues,” Kittell said.
  • Flood watches are also in effect across the San Bernardino, Riverside and Santa Ana mountains, as well as portions of the Inland Empire in proximity to the foothills and inland Orange County until Wednesday afternoon.

California continues to deal with damage from March storms: surging rivers, mudslides, breached levees and displacement in flooded towns.

March 12, 2023