Millions of people across parts of California, Oregon, and Washington are under urgent heat alerts as the National Weather Service (NWS) warns of “lethal temperatures” and elevated overnight heat that could pose serious health risks.
Where the Heat Warnings Are in Place
An Extreme Heat Warning is in effect from mid-Sunday morning to Tuesday evening across large areas of:
- Northern California, including the Sacramento Valley, Shasta County, and the surrounding foothills.
- The Portland, Oregon metro area, extending into southwest Washington, including Vancouver and the Columbia River Gorge.
What Conditions People Should Expect
The NWS says that the region will experience prolonged, “dangerously hot conditions” with little overnight relief:
- California: Temperatures could reach up to 110 F, with overnight lows staying in the 70s, preventing temperatures from dropping, offering little nighttime relief
- Oregon/Washington: Highs of between 95 and 100 F are expected, with nighttime temperatures remaining in the low-to-mid 60s.
The heat is expected to reach its peak through Sunday and Monday, with a slight cooling trend beginning on Tuesday.
The NWS warns that this level of heat corresponds to a “Major Heat Risk,” meaning anyone without adequate ways to cool down or hydrate properly is likely to be affected. The National Oceanic and Atmospheric Administration (NOAA) supports this by saying that “extreme heat with no overnight relief [affects] anyone without cooling/hydration as well as health systems, industries, and infrastructure.”
How Unusual Is This Heat?
While summer temperatures in inland California can regularly exceed 100 F, this level of prolonged heat — especially combined with warm nights — severely increases health risks.
The California Office of Environmental Health Hazard Assessment says that “long periods of high temperatures are particularly dangerous when nights remain warm… warm nights do not allow the body to recover after a hot day.”…