Historical weather data, all-time temperature records, and monthly climate averages for Napa, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5 in Napa runs mild, with average highs of 68° and lows around 44° — classic early spring wine country weather. There's a 30% chance of rain today, though snow is essentially unheard of on this date. The record books show a 55-degree swing in history: a balmy 86° back in 1957 and a sharp 31° freeze in 1918.
Napa's weather has serious range for a place known for gentle growing seasons — the all-time high hit a brutal 114° on September 6, 2022, while the coldest recorded day bottomed out at 14° on December 22, 1990. The wettest single day on record dropped 5.85 inches of rain on November 21, 1977, and the valley has even seen snow, with 2.5 inches falling way back on January 6, 1907.
Napa's summer is long and warm, with highs in the low 80s from June through September and a peak around July 9–15. If you're avoiding rain, stick to summer — the wettest stretch runs late December, averaging 1.34 inches in just one week. Winter stays mild by most standards, with January highs holding around 56–57°.