Historical weather data, all-time temperature records, and monthly climate averages for South Pasadena, CA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in South Pasadena sits right in that pleasant shoulder season sweet spot — 120 years of data puts the average high at a comfortable 72° with a low of 48°. There's a modest 21% chance of rain, a reminder that the wet season hasn't fully let go yet. The date's wild range, from a 99° scorcher in 1989 down to a 35° freeze in 1918, shows just how much Southern California can surprise you in early spring.
South Pasadena's all-time records tell the story of a place that can genuinely punish you. The mercury hit a staggering 115° on September 6, 2020 — one of the most brutal heat events in the region's recorded history — while the coldest day on record bottomed out at 21° back in January 1913. Rainfall extremes are no joke either: a single day in March 1938 dumped 7.7 inches, and the town even saw 3 inches of snow in January 1949.
South Pasadena is a year-round destination with a genuinely mild range — average highs stay between 66° in early January and 90° in late July and early August. If you're heat-sensitive, skip late summer; if you want the greenest version of the San Gabriel Valley, aim for late winter when February's rains peak around 1.23 inches per week. The city rarely gets truly cold, with even the coolest weeks averaging highs in the mid-60s.