Foster City, California Weather
Summer solstice light stretched thin. Day 88 of spring. Read this microseason across nine climate regions →
Foster City weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 15Overcast——77°57°—
- TuesdayJun 16Overcast——75°55°-2°
- WednesdayJun 17Clear——80°60°+5°
- ThursdayJun 18Clear——75°57°-5°
- FridayJun 19Partly Cloudy——71°57°-4°
- SaturdayJun 20Overcast——68°57°-3°
- SundayJun 21Clear——77°55°+9°
AQI 50 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 14.7 µg/m³ (AQI 61) with a 0.66 fine-to-coarse ratio and 4 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 14.7 µg/m³ (AQI 61) with a 0.66 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.66
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 5:57 AM
- Moonset
- 8:52 PM
- In sign
- ♊︎ Gemini
Summer solstice light stretched thin
Foster City at a glance
- Today vs. normal: 19°F below the seasonal normal for this latitude
- Last frost: April 1 (climatological average for this latitude)
- Microseason: Jun 11–15
- Planting window: Stake and prune tomato suckers. Watch for squash vine borers.
15-Day Forecast — Foster City
- Mon77°57°0%
- Tue75°55°0%
- Wed80°60°0%
- Thu75°57°1%
- Fri71°57°1%
- Sat68°57°1%
- Sun77°55°1%
- Mon81°57°0%
- Tue78°57°0%
- Wed70°56°0%
- Thu81°55°0%
- Fri76°54°0%
- Sat73°57°0%
- Sun79°57°0%
- Mon73°57°0%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of June 15, 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.
ZIP codes in Foster City
- 94404