Heat stress in Oakland
Bay-cooled and temperate most of the year, with rare inland-driven heat spells that bite hard in a city where AC is scarce.
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 Oakland on the live mapReading heat stress in Oakland
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 Oakland because bay-cooled and temperate most of the year, with rare inland-driven heat spells that bite hard in a city where AC is scarce. 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 Oakland usually gets
Across 2015–2024, Oakland averaged a 74°F daily high in summer: 171st hottest of the 174 metros we track, and September is typically the warmest month.
Most of the heat here sits below the extremes: around 8 days a year top 90°F, and only about 1 reach 100°F.
Humidity is the real story: summer averages about 76%, so sweat evaporates poorly and heat stress runs well above what a 74°F afternoon suggests.
The ceiling is a long way above the routine: the hottest day in this sample hit 110°F, about 36°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 Oakland: common questions
How hot does it usually get in Oakland?
Across 2015–2024, Oakland averaged a 74°F daily high through summer, with about 8 days a year at or above 90°F and 1 at or above 100°F. September 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 Oakland?
September has the highest average daily high in Oakland. Humidity is the real story here: summer averages about 76%, 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 Oakland right now?
The reading at the top of this page is the current wet-bulb globe temperature for Oakland, 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 Oakland?
Air temperature ignores humidity, wind, and sun: the things that decide whether heat is dangerous. Oakland's climate (bay-cooled and temperate most of the year, with rare inland-driven heat spells that bite hard in a city where AC is scarce.) 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 Oakland?
September is the peak month in Oakland, 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: 8 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 Oakland’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/oakland-ca" width="340" height="150" style="border:0" title="Live WBGT: Oakland, CA" loading="lazy"></iframe>Paste it into any website. The badge updates itself and links back here. Add ?theme=light for light sites.