why is it so foggy in san diego

San Diego has been extra foggy lately because cool, moist air near the surface is getting trapped under a stable layer of warmer air aloft after recent stormy, rainy weather, which is classic post-storm coastal fog setup. The heavy New Year’s rain and lingering clouds over Southern California are keeping the ground and lower atmosphere very moist, so when nights are cool and winds stay light, that moisture easily condenses into fog, especially near the ocean and low-lying areas.

Quick Scoop

• Recent strong storms soaked the region, leaving lots of low‑level moisture in the air and in the soil.

• As skies partially clear at night, the ground cools, the air near the surface cools with it, and that humid air hits saturation, turning into fog.
• A stable high‑pressure pattern over California acts like a lid, trapping that cool, moist air near the surface so the fog and low clouds hang around instead of burning off quickly.

• On the coast, the cool Pacific plus moist onshore flow feeds additional marine-layer fog, so coastal neighborhoods see more persistent gray than inland spots.

Why it feels worse right now

• The first days of 2026 included one of the rainiest days on record in San Diego, boosting humidity and making fog more likely the following mornings.

• Forecasts for late 2025 into early 2026 called for repeated clouds and showers over San Diego County, which means the atmosphere has stayed primed for fog instead of drying out.

• When a stable pattern lingers for days, fog and low stratus can repeat morning after morning, making it feel like “permanent” gloom even though it’s just a particular short‑term pattern.

A bit of bigger-picture context

• Elsewhere in California, a similar setup recently produced a massive, persistent fog bank (tule‑style fog) over the Central Valley: wet ground, calm winds, and a strong high‑pressure “lid.”

• While San Diego doesn’t get tule fog like the interior valleys, it can experience the same basic physics on a milder, marine-layer version, especially in winter.
• These episodes tend to break when either a new storm mixes the atmosphere or offshore flow and drier air arrive, so the current extra-foggy pattern is unlikely to last all winter.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.