San Diego Weather Today: Heavy Rain and Flood Watch for New Year’s Day 2026

If you’re in America’s Finest City this New Year’s Day, keep the umbrella handy and ditch any beach plans. San Diego is waking up to a soggy and unusually wet start to 2026, with heavy rain, a dense marine layer, and an active Flood Watch in effect for surrounding regions. While the current temperature is a mild 63°F, the forecast promises a damp and gray day with near-certain precipitation.

This weather marks a significant shift from the typical sunny San Diego stereotype and aligns with broader climate patterns affecting Southern California. Understanding today’s conditions and the larger forces at play, like the developing La Niña, is key to planning your day and the week ahead.

Current Conditions & Today’s Forecast

As of 8:00 AM PST on Thursday, January 1, 2026, the weather in San Diego is dominated by a thick blanket of cloud cover and steady rainfall. Visibility is reduced to just over 3 kilometers (about 1 mile), creating a misty, subdued atmosphere across the county.

Right Now in San Diego

Full Day Forecast: Thursday, January 1

Active Weather Alerts and Regional Impact

The National Weather Service in Los Angeles/Oxnard has issued a Flood Watch that remains in effect through this evening for many areas north of San Diego, including parts of Los Angeles, Ventura, and Santa Barbara counties. While the watch area is primarily to our north, it underscores the potency of this storm system moving through Southern California.

“…FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING…” – National Weather Service Los Angeles/Oxnard, 1217 AM PST Thu Jan 1 2026.

Residents should be aware of potential for localized flooding, especially in low-lying areas, and exercise caution while driving due to reduced visibility and wet roads. This is a stark contrast to the heat advisories that have impacted inland valley areas in recent seasons, highlighting California’s volatile weather swings.

Weekend Outlook and Extended Forecast

The rain is expected to taper off as we move into the weekend, offering some relief from the persistent downpours.

Keep an eye on local forecasts from sources like KGTV for updates on the weekend’s conditions as the system fully passes.

The Big Picture: La Niña’s Role in San Diego’s Winter

This rainy pattern invites questions about the larger climate drivers at work. Forecasters are currently watching the development of La Niña conditions this fall and winter. Traditionally, a strong La Niña favors rain in the Pacific Northwest and drier conditions in Southern California. However, recent years have shown this isn’t a guarantee.

“We can’t trust El Niño and La Niña completely to make accurate water year predictions,” notes a recent study highlighted by climate scientists. Atmospheric rivers act as “wild cards,” capable of dumping significant rain on Southern California regardless of the La Niña forecast, as seen in the wet 2022-23 winter.

For San Diego, a weak La Niña—which is currently anticipated—often correlates with near-normal temperatures and can still allow for periods of above-average rainfall, much like what the region is experiencing today. This complexity makes precise long-term forecasting a challenge.

Common Questions

Is there a flood warning in San Diego today?

As of the morning of January 1, 2026, there is a Flood Watch in effect for many counties north of San Diego (like Los Angeles and Ventura) issued by the National Weather Service. While San Diego proper may not be under the official watch, the heavy rain creates a risk for localized flooding. Always check the latest alerts from the NWS.

What is the weather in San Diego for New Year’s Day 2026?

The weather is wet and cloudy with heavy rain. Expect a high near 65°F and a low around 55°F with a 100% chance of precipitation throughout the day. Wind will be from the south-southeast at 8-10 mph.

How does La Niña affect San Diego’s winter weather?

La Niña typically brings cooler temperatures and can lead to drier conditions in Southern California. However, its effects are not reliable. Weak La Niña events can still result in near-normal rain, and atmospheric rivers can cause very wet periods regardless of the La Niña forecast, making each winter unique.

Will it rain all weekend in San Diego?

The heavy rain is expected to be concentrated on New Year’s Day. The forecast for Friday, January 2, currently calls for mostly cloudy skies, suggesting a break in the rain. Conditions for the rest of the weekend should become clearer as the storm system moves out.