San Mateo, California Weather
Coastal fog thickens at dawn. Day 78 of spring. Read this microseason across nine climate regions →
San Mateo weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 5Mostly Clear——81°51°—
- SaturdayJun 6Overcast——70°53°-11°
- SundayJun 7Overcast——77°52°+7°
- MondayJun 8Overcast23%—70°55°-7°
- TuesdayJun 9Light Drizzle25%—71°57°+1°
- WednesdayJun 10Clear——84°54°+13°
- ThursdayJun 11Clear——93°61°+9°
AQI 32 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 9.3 µg/m³ (AQI 51) with a 0.65 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
PM × Wind × Precip
PM2.5 at 9.3 µg/m³ (AQI 51) with a 0.65 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.65
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 7:06 AM
- Moonset
- 5:27 PM
- In sign
- ♒︎ Aquarius
Coastal fog thickens at dawn
San Mateo at a glance
- Today vs. normal: 22°F below the seasonal normal for this latitude
- Last frost: April 1 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.