Vallejo

What is the climate like in Vallejo?

The best time to visit Vallejo is typically April – October, with trip comfort peaking in June (9.2/10). Vallejo is warmest in September, when daily highs average 83°F (28°C), and coolest in December, when lows fall to about 43°F (6°C). The wettest month is typically January and the driest is July; the year sees roughly 21 in (532 mm) of precipitation.

• Best time to visitApril – October — comfort peaks in June (9.2/10)
• Warmest monthSeptember — average high 83°F (28°C)
• Coolest monthDecember — average low 43°F (6°C)
• Wettest monthJanuary (4.5 in (114 mm))
• Driest monthJuly (0.0 in (0 mm))
• Annual precipitation21 in (532 mm)
• Based on2016-2025 daily ERA5 reanalysis data (10-year normals)
• Records fromNapa State Hospital, 19 km away (1893-2026)