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San Jose weather alerts

1 active alert for San Jose, California right now: a Heat Advisory.

26 in the last 30 days 26 in 12 months (since Aug 30) most common: Heat Advisory Get alerts on your phone →

Active alerts for Santa Clara County

NWS issues alerts by county; San Jose is in Santa Clara County. Refreshed every few minutes; times in PDT.

Moderate Expected

Heat Advisory

Issued Sun, Oct 4, 11:01 PM PDT by NWS San Francisco CA Until Wed, Oct 7, 10:00 PM PDT (in 3 days)

Area: Sonoma Coastal Range; North Bay Interior Mountains; North Bay Interior Valleys; San Francisco Bay Shoreline; East Bay Interior Valleys; Santa Cruz Mountains; Santa Clara Valley Including San Jose; Eastern Santa Clara ...

* WHAT...Hot conditions with maximum temperatures in the mid-90s to low-100s. Mild minimum temperatures and weak onshore flow will limit overnight relief. * WHERE...The East Bay and San Francisco Bay Shoreline, North Bay Interior Mountains and Valleys, The Santa Clara Valley and Eastern Hills, The Santa Cruz Mountains, Interior Monterey County and the San...

What it means: Heat index values high enough to cause heat illness with prolonged exposure. Drink water, stay in air conditioning and check on neighbours.

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Where

Santa Clara County on the map

Alert polygons are NWS's own. Forecast Bar's radar shows the same warnings over live precipitation, with future radar and lightning. See the radar.

Last 30 days

Recent alerts for Santa Clara County

AlertIssuedEndedIssued by
Heat Advisory Oct 4, 9:34 PM Oct 7, 10:00 PM San Francisco CA
Heat Advisory Oct 3, 7:48 PM Oct 7, 10:00 PM San Francisco CA
Heat Advisory Oct 3, 12:00 PM Oct 7, 10:00 PM San Francisco CA
Heat Advisory Oct 3, 7:32 AM 10:00 PM San Francisco CA
Heat Advisory Oct 3, 2:02 AM 10:00 PM San Francisco CA
Heat Advisory Oct 2, 8:53 PM 10:00 PM San Francisco CA
Heat Advisory Oct 2, 11:16 AM 10:00 PM San Francisco CA
Heat Advisory Oct 2, 1:25 AM Oct 4, 10:00 PM San Francisco CA
Coastal Flood Advisory Oct 1, 7:39 PM Oct 2, 6:00 PM San Francisco CA
Coastal Flood Advisory Oct 1, 12:20 PM Oct 2, 6:00 PM San Francisco CA
Heat Advisory Oct 1, 9:43 AM Oct 4, 10:00 PM San Francisco CA
Coastal Flood Advisory Sep 30, 3:46 PM Oct 1, 5:00 PM San Francisco CA
Coastal Flood Advisory Sep 29, 2:54 PM Oct 1, 5:00 PM San Francisco CA
Coastal Flood Advisory Sep 28, 9:16 PM Oct 1, 5:00 PM San Francisco CA
Coastal Flood Advisory Sep 28, 10:39 AM Oct 1, 5:00 PM San Francisco CA
Coastal Flood Advisory Sep 28, 10:32 AM Oct 1, 5:00 PM San Francisco CA
Coastal Flood Advisory Sep 27, 8:17 PM Oct 1, 5:00 PM San Francisco CA
Heat Advisory Sep 10, 4:47 PM Sep 10, 10:00 PM San Francisco CA
Coastal Flood Advisory Sep 10, 12:37 AM Sep 10, 1:00 AM San Francisco CA
Heat Advisory Sep 9, 3:14 AM Sep 10, 10:00 PM San Francisco CA
Coastal Flood Advisory Sep 9, 1:01 AM Sep 10, 1:00 AM San Francisco CA
Heat Advisory Sep 8, 7:33 PM Sep 10, 10:00 PM San Francisco CA
Heat Advisory Sep 8, 1:15 PM Sep 10, 10:00 PM San Francisco CA
Coastal Flood Advisory Sep 8, 9:03 AM Sep 10, 1:00 AM San Francisco CA
Heat Advisory Sep 7, 10:27 AM Sep 10, 10:00 PM San Francisco CA

Pattern

What Santa Clara County gets alerted for

Every alert that named Santa Clara County in the last 12 months, by type. Records begin August 30, 2026, so this fills in over the year.

Heat Advisory
15
Coastal Flood Advisory
11

Plain English

What these alerts mean

A warning means the hazard is happening or about to; a watch means conditions favour it; an advisory is a lesser hazard still worth planning around.

Heat Advisory

Heat index values high enough to cause heat illness with prolonged exposure. Drink water, stay in air conditioning and check on neighbours.

Coastal Flood Advisory

Minor coastal flooding is expected, usually around high tide. Expect water on low-lying roads near the shore.

Nearby

Alerts near San Jose

Cities

Santa Clara, CA1 Milpitas, CA1 Cupertino, CA1 Sunnyvale, CA1 Fremont, CA1 Mountain View, CA1

Neighbouring counties in California

Santa Cruz County1 Alameda County1 San Mateo County1 San Benito County1 San Joaquin County1 Stanislaus County1 Monterey County1 Merced County1 All of California →

Questions

About San Jose alerts

How do I get San Jose weather alerts on my iPhone?

Install Forecast Bar, add San Jose as a location, and turn on severe weather alerts. Every NWS warning, watch and advisory for Santa Clara County then arrives as a push notification at the moment of issue, with Critical Alerts available for the most dangerous warnings. Forecast Bar also runs on iPad, Apple Watch, Mac and Apple TV.

Where do these alerts come from?

From the National Weather Service alert feed (api.weather.gov). NWS issues alerts by county and by forecast zone; this page lists every product that names Santa Clara County, the county San Jose sits in. Forecast Bar checks the feed continuously and this page refreshes within a few minutes of a change.

What is the difference between a watch, a warning and an advisory?

A warning means the hazard is occurring, imminent or very likely: act now. A watch means conditions are favourable for it to develop: prepare and stay informed. An advisory covers a hazard that is less serious than a warning but can still cause real inconvenience or danger if you are not ready for it.

Can I get this data as JSON?

Yes. /weather-alerts/ca/san-jose.json returns the active alerts, the last 30 days and the 12-month counts for San Jose, refreshed every minute. Please cache responses and credit National Weather Service as the source.

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