Unseasonably Cold Air Sweeps Central California A deep Arctic air mass will move into Central California later this week, driving temperatures 8‑10 °F below normal for early January [1]. The National Weather Service San Francisco office issued an extreme cold watch covering more than 4 million residents across the Bay Area, North Bay interior valleys, Santa Clara Valley, Salinas and Carmel valleys, and parts of Monterey County [1]. The watch is set for the overnight of Jan 9, from 1 a.m. to 9 a.m., when temperatures are expected to reach the upper 20s in interior Monterey and San Benito counties and low‑mid‑30s elsewhere [1].

Vulnerable Populations Face Heightened Danger Meteorologists warned that temperatures at or below 35 °F can be deadly for people without shelter, with prolonged exposure risking hypothermia [1]. The alert highlights risks to unhoused individuals, seniors, children, outdoor pets, and livestock, and notes the potential for frozen plumbing that could damage homes and businesses [1]. Public‑health officials emphasized the need for warming centers and safe heating practices to protect these groups [1].

Agricultural and Infrastructure Impacts Expected Forecast lows in the upper 20s threaten sensitive crops and vegetation, raising concerns about frost damage to orchards and field plants [1]. Frozen pipes are likely in the affected valleys, posing a risk of water‑supply interruptions and costly repairs [1]. The NWS also cautioned that the cold could impair outdoor livestock operations and damage infrastructure reliant on above‑ground water lines [1].

Authorities Recommend Safety Measures and Anticipate Warming Local officials urged residents to use portable heaters safely, avoid indoor generators or grills to prevent carbon‑monoxide poisoning, and check for available warming centers [1]. Recommendations included dressing in layers, protecting pets and livestock, and covering vulnerable crops [1]. Forecasters expect temperatures to moderate gradually on Saturday, and the watch could be upgraded to an extreme cold warning if conditions worsen [1].