Alum Rock

What is the climate like in Alum Rock?

The best time to visit Alum Rock is typically May – October, with trip comfort peaking in July (9.5/10). Alum Rock is warmest in August, when daily highs average 84°F (29°C), and coolest in February, when lows fall to about 42°F (5°C). The wettest month is typically January and the driest is July; the year sees roughly 24 in (600 mm) of precipitation.

• Best time to visitMay – October — comfort peaks in July (9.5/10)
• Warmest monthAugust — average high 84°F (29°C)
• Coolest monthFebruary — average low 42°F (5°C)
• Wettest monthJanuary (5.3 in (136 mm))
• Driest monthJuly (0.0 in (0 mm))
• Annual precipitation24 in (600 mm)
• Based on2016-2025 daily ERA5 reanalysis data (10-year normals)
• Records fromSan Jose, 9 km away (1893-2026)