San Francisco started the day in familiar territory with cool, mostly clear air around 53°F, but that comfort window is about to slam shut. A strong ridge of high pressure is moving in and will crank up temperatures citywide, with highs near 78°F today and climbing into the 80s early next week. The National Weather Service is flagging this as a multi-day heat event that will bring above-normal temperatures to the Bay Area and Central Coast, so residents should plan for hot afternoons and only limited overnight cooldowns through the week.
What To Expect This Week
Today is expected to be mostly sunny with light northwest winds and a high near 78°F. Things really heat up tomorrow, when highs jump to around 84°F, then push into the upper 80s on Tuesday. Temperatures will stay well above seasonal norms through midweek, and some interior Central Coast locations could flirt with the upper 90s later in the week. Overnight lows will likely stay in the upper 50s to low 60s, so it may not cool off as much as your apartment usually does at night.
A Heat Advisory is in effect from 10 a.m. Monday, March 16, through 8 PM Friday, March 20, for the Bay Area and Central Coast, according to the National Weather Service.
Coastal Relief, Inland Heat
A shallow marine layer will lend the immediate coast and waterfront neighborhoods a bit of relief overnight and in the early morning. Once daytime heating kicks in, that layer is expected to compress or erode, so even coastal areas will run warmer than usual. The real hot spots will be inland valleys and hill neighborhoods where the ocean influence weakens and the heat can really settle in.
Winds are forecast to stay generally light, so the main issue will be the heat itself rather than gusty conditions. In other words, it is less about being blown around and more about slowly roasting.
Precautions And Where To Cool Off
Try to avoid strenuous outdoor activity during the hottest part of the day, roughly 10 AM to 4 or 5 PM. Stay hydrated, check in on older adults and anyone with underlying health conditions, and take breaks in the shade or in air-conditioned areas when you can. Never leave children or pets in a parked car, even briefly, since interior temperatures can become deadly within minutes.
The City of San Francisco maintains a heat resources page with an interactive map of cooling centers, pools, and water stations. You can call 311 or use the online map to find a nearby cool spot, per the City of San Francisco.
Outdoor Workers, Boaters And Fire Risk
Employers with outdoor crews should reschedule heavy labor to the cooler morning or evening hours, provide plenty of drinking water and rest breaks, and watch workers closely for signs of heat illness. Symptoms can sneak up on people who are trying to power through the day.
Boaters should check the marine forecast before heading out, since small craft advisories may affect some offshore waters. On land, the prolonged dry stretch will increase the risk of grass fires, so avoid open flames and use caution with tools or equipment that could spark.
If someone shows signs of heat stroke, such as confusion or altered behavior, get them to a cool place immediately and call 911. Quick action can make all the difference in dangerous heat.
