Saturday morning in the Bay Area was muggy and mild, if not warm. Temperatures only cooled down to the upper 50s to low 60s across much of the Bay Area – five to 15 degrees above average for late winter.

For San Francisco and Oakland, it was a record warm start to the last day of the month. With temperatures only dipping down to 62 in San Francisco, it was the warmest morning in recorded history during the month of February, and those records go back to 1875. The old record was 61° in 1985. 

Oakland’s old record was also in 1985, when the low was 60°. Now Oakland’s new record for warmest February morning was set on Saturday, with a low of 61. It was also extremely muggy, with dew points in the upper 50s and humidity over 90%.

Why? It mostly has to do with the extremely warm blob of water sitting off the Bay Area’s coast. It’s technically called a “Marine Heatwave” and the one we are currently dealing with began in May 2025.

Normally this time of year, ocean temperatures are near 53 degrees – but it was about 57 near the Golden Gate Bridge as of Saturday morning.

Warmer ocean water warms up the air above it, and then winds carry the warmer air over land and warms us up. The warmer water also increases evaporation, raising moisture content in the air (aka humidity).

So now you know, you can blame the warm blob of ocean water for the reason it was so muggy.