Northern and Central California are deep inside a dangerous multi-day heat event, with an Extreme Heat Warning in effect for the Redding area and the Sacramento Valley through Tuesday night, Heat Advisories stretching from the Oregon border to the San Joaquin Valley, and temperature forecasts reaching 112°F in the Trinity River Canyon — among the hottest readings on record for any California location in June.
Extreme Heat Warning: Redding, Chico and the Sacramento Valley
The most severe alert comes from the National Weather Service in Sacramento, which has issued an Extreme Heat Warning in effect through 11 PM PDT Tuesday for a wide swath of Shasta, Tehama and Butte counties. High temperatures up to 110°F are expected in Redding, Red Bluff, Chico, Oroville, Anderson, Paradise and Shasta Lake — communities that already sit in one of the hottest natural environments in the United States.
The Extreme Heat Warning is a tier above a standard Heat Advisory and is issued specifically when “dangerously hot conditions” are expected to pose serious health risks to the general population — not just vulnerable groups. Overnight lows will only drop into the 70s, denying the body the nighttime cooling it needs to recover from daytime heat exposure.
According to WeatherNorCal’s current forecast, “warm overnight lows in the upper 60s to mid-70s will offer minimal thermal relief, driving widespread major heat risks” through Tuesday before the ridge finally breaks down Wednesday.
112°F in the Trinity River Canyon
The single hottest temperature forecast in the entire alert package belongs to northwestern and central Trinity County — Weaverville, Junction City, Del Loma, Big Bar and Helena — where the NWS Eureka office is forecasting temperatures of 100 to 112°F through Tuesday. The Trinity River Canyon is notorious for trapping heat: the steep walls channel and concentrate hot air while blocking afternoon breezes. Interior Humboldt County — Hoopa, Willow Creek and Weitchpec — is expected to reach 99 to 110°F.
Both zones carry a “Moderate to Major HeatRisk” designation. The Eureka office noted that hot temperatures “may cause heat illnesses especially for those without cooling or hydration” — a genuine concern in remote communities where air conditioning is not universal and the nearest hospital may be an hour away.
Heat Advisories Fan Out Across the Region
Central California’s San Joaquin Valley — Fresno, Bakersfield, Visalia, Merced, Hanford, Porterville, Delano and Tulare — faces temperatures up to 102°F through Tuesday, flagged as a “Moderate Risk” for heat illness by the NWS Hanford office.
Siskiyou County and the Oregon border — including Yreka, Mount Shasta City, Weed, Dunsmuir, Happy Camp, Etna and Seiad Valley — faces 94 to 104°F across the central county and 100 to 110°F in the Scott and Salmon river canyons of western Siskiyou. The Klamath Basin in Oregon, including Klamath Falls, is under a Heat Advisory with highs of 90 to 97°F.
Western Nevada’s Basin and Range — Fallon, Fernley, Lovelock and Silver Springs — faces 98 to 102°F on Tuesday with overnight lows of 65 to 70°F and an “isolated Major HeatRisk” in the lower valleys according to the NWS Reno office.
How to Stay Safe Through Tuesday
Shasta County has opened emergency cooling centers for residents without air conditioning. Check local county emergency management for locations and hours.
For everyone in the warning and advisory zones: drink water before you feel thirsty, stay indoors during peak heat from 11 AM to 8 PM, check on elderly neighbors and never leave children or pets in a parked vehicle. Heat stroke — hot red skin, rapid pulse, confusion — is a 911 emergency. Relief is forecast by Wednesday afternoon, with temperatures dropping into the mid-to-upper 80s by Thursday.
