Historical weather data, all-time temperature records, and monthly climate averages for South El Monte, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
South El Monte sits in the San Gabriel Valley, where summer heat builds fast and lingers. Historically, days like today have seen highs push into the upper 80s to low 90s depending on the time of year — part of a climate shaped by surrounding mountains and the occasional offshore flow.
South El Monte doesn't mess around at the extremes. The mercury hit a scorching 118° on July 6, 2018, and bottomed out at 29° on January 14, 2013 — a 89-degree swing that tells you this valley can surprise you in either direction.
Summer is the main event here, with average highs peaking around 95° during late August into early September and staying above 90° from July through mid-September. Winter is mild by most standards — highs hold in the upper 60s to low 70s from December through February. Rainfall is minimal year-round, but what little you get typically falls in January.