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Weather in Foster City, United States 🇺🇸

Current Weather in Foster City

Heat Advisory issued September 8 at 7:33PM PDT until September 10 at 10:00PM PDT by NWS San Francisco CA
Overcast
19°C
Feels like 20°C. Overcast.
🌬️ 4 km/h NE
💧 66% Humidity
🧭 1018 hPa
👁️ 10.0 km Visibility
☀️ UV Index: 0.4
🌡️ Dew Point: 13°C
🌅 Sunrise: 06:46 AM
🌇 Sunset: 07:26 PM
Map Overlays:

As of now, Foster City is 19°C and overcast, feeling like 20°C. Relative humidity is 66%, with winds around 4 km/h, and the UV index is 0 (low). Looking ahead, Foster City should sit between roughly 14°C and 35°C over the coming days. ⚠️ Heat Advisory issued September 8 at 7:33PM PDT until September 10 at 10:00PM PDT by NWS San Francisco CA

Hourly Forecast for Foster City

09:00
Overcast
23°
12%
10:00
Overcast
26°
10%
11:00
Overcast
30°
8%
12:00
Overcast
32°
8%
13:00
Overcast
35°
9%
14:00
Overcast
28°
9%
15:00
Overcast
28°
9%
16:00
Overcast
29°
9%
17:00
Overcast
29°
9%
18:00
Overcast
27°
9%
19:00
Partly Cloudy
26°
4%
20:00
Cloudy
24°
8%
21:00
Overcast
23°
9%
22:00
Cloudy
22°
7%
23:00
Partly Cloudy
22°
2%
00:00
Partly Cloudy
22°
3%
01:00
Overcast
21°
9%
02:00
Overcast
22°
8%
03:00
Cloudy
21°
6%
04:00
Partly Cloudy
21°
4%
05:00
Overcast
19°
13%
06:00
Patchy rain nearby
19°
14%
07:00
Patchy rain nearby
19°
20%
08:00
Patchy rain nearby
20°
17%

14-Day Forecast for Foster City

Wed, Sep 09
Overcast Overcast
35° / 17°
Thu, Sep 10
Overcast Overcast
28° / 16°
Fri, Sep 11
Sunny Sunny
23° / 14°
Sat, Sep 12
Sunny Sunny
20° / 13°
Sun, Sep 13
Sunny Sunny
22° / 12°
Mon, Sep 14
Sunny Sunny
23° / 12°
Tue, Sep 15
Sunny Sunny
21° / 13°
Wed, Sep 16
Sunny Sunny
22° / 12°
Thu, Sep 17
Partly Cloudy Partly Cloudy
22° / 13°
Fri, Sep 18
Sunny Sunny
22° / 13°
Sat, Sep 19
Sunny Sunny
22° / 12°
Sun, Sep 20
Sunny Sunny
24° / 12°
Mon, Sep 21
Sunny Sunny
26° / 13°
Tue, Sep 22
Sunny Sunny
27° / 16°

Additional Forecasts for Foster City

Air Quality

💨 US EPA Index 2 (Moderate)
CO (Carbon Monoxide) 265.0 μg/m³
O₃ (Ozone) 24.0 μg/m³
NO₂ (Nitrogen Dioxide) 30.4 μg/m³
SO₂ (Sulphur Dioxide) 1.4 μg/m³
PM2.5 (Fine particles) 20.4 μg/m³
PM10 (Coarse particles) 23.7 μg/m³

Historical Weather

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Best Time to Be Outside in Foster City Today

The most comfortable window in Foster City today looks like 17:00 to 20:00, when it is around 27°C. It should stay dry through that window. No significant rain is expected in the next several hours.

Frequently Asked Questions about Weather in Foster City

What is the temperature in Foster City right now?

Foster City is sitting at 19°C (67°F) right now, overcast (feels like 20°C).

What's the weather like in Foster City right now?

Current weather in Foster City: Overcast, humidity 66%, wind 4 km/h NE.

What is today's forecast for Foster City?

Today in Foster City: high 35°C, low 17°C, overcast. Chance of rain: 10%.

What is the 7-day weather forecast for Foster City?

Daily highs and lows for Foster City:

  • 2026-09-09: 35°C / 17°C
  • 2026-09-10: 28°C / 16°C
  • 2026-09-11: 23°C / 14°C
  • 2026-09-12: 20°C / 13°C
  • 2026-09-13: 22°C / 12°C
  • 2026-09-14: 23°C / 12°C
  • 2026-09-15: 21°C / 13°C
Is it going to rain in Foster City today?

There is a 10% chance of rain in Foster City today.

What is the wind speed in Foster City right now?

Wind in Foster City is currently 4 km/h (2 mph) from the NE.

What is the UV index in Foster City right now?

The UV index in Foster City is currently 0.4 (low). Sun protection is recommended when the index is 3 or higher.

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