Heat stress in Fremont
Bay-moderated much of the year, with hot inland-valley air and heat waves that push afternoon heat stress higher.
Light precautions for intense activity. Keep water handy.
Wet-bulb globe temperature via the Liljegren (2008) method. This page is cached and refreshes in the background, so the live badge below can be a few minutes ahead of it.
View Fremont on the live mapReading heat stress in Fremont
Wet-bulb globe temperature (WBGT) is the heat measure that actually tracks danger to the body. Unlike the plain air temperature on your phone, it folds in humidity, wind, and direct sun: the factors that decide whether your sweat can still cool you. It’s the standard the military, athletic associations, and occupational-safety bodies use to call when outdoor activity is no longer safe.
That matters in Fremont because bay-moderated much of the year, with hot inland-valley air and heat waves that push afternoon heat stress higher. The number above is the live outdoor WBGT for the city right now; tap through to the live map to inspect any neighborhood, scrub the forecast hour by hour, and see the 7-day outlook.
How hot Fremont usually gets
Across 2015–2024, Fremont averaged a 79°F daily high in summer: 157th hottest of the 174 metros we track, and August is typically the warmest month.
Most of the heat here sits below the extremes: around 10 days a year top 90°F, and only about 1 reach 100°F.
Humidity is the real story: summer averages about 66%, so sweat evaporates poorly and heat stress runs well above what a 79°F afternoon suggests.
The ceiling is a long way above the routine: the hottest day in this sample hit 110°F, about 31°F past a normal summer afternoon.
Daily high temperatures and humidity from ERA5 reanalysis, 2015–2024 (hottest day in the sample: 2022-09-06). These are climate averages for context: the reading at the top of this page is the live one.
Heat in Fremont: common questions
How hot does it usually get in Fremont?
Across 2015–2024, Fremont averaged a 79°F daily high through summer, with about 10 days a year at or above 90°F and 1 at or above 100°F. August is typically the hottest month, and the hottest day in that sample reached 110°F. Figures are from ERA5 daily reanalysis.
When is the hottest time of year in Fremont?
August has the highest average daily high in Fremont. Humidity is the real story here: summer averages about 66%, so sweat evaporates poorly and heat stress runs well above what the temperature alone suggests. Use the forecast on this page to plan around the specific days that matter.
What is the WBGT in Fremont right now?
The reading at the top of this page is the current wet-bulb globe temperature for Fremont, California, computed from live weather by the Liljegren (2008) method and labeled with how recently it updated. For an exact reading at your own neighborhood, plus an hour-by-hour forecast, open the live map.
Why is WBGT more useful than the temperature for Fremont?
Air temperature ignores humidity, wind, and sun: the things that decide whether heat is dangerous. Fremont's climate (bay-moderated much of the year, with hot inland-valley air and heat waves that push afternoon heat stress higher.) is exactly why a single "feels-like" or thermometer reading can understate the real risk. WBGT captures all of it in one number.
When is heat most dangerous in Fremont?
August is the peak month in Fremont, and within a day heat stress is highest in the early-to-mid afternoon when sun load is greatest. Dangerous days are uncommon here, which is its own hazard: 10 days a year reach 90°F, and people are least acclimatized when they arrive. Use the forecast on this page to find the window that works.
Put Fremont’s live heat stress on your site
A self-updating WBGT badge for schools, teams, camps, and local sites: it always shows the current reading and links back here.
<iframe src="https://wetbulbtracker.com/embed/fremont-ca" width="340" height="150" style="border:0" title="Live WBGT: Fremont, CA" loading="lazy"></iframe>Paste it into any website. The badge updates itself and links back here. Add ?theme=light for light sites.