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South Pasadena climate

Typical historical weather for South Pasadena, United States, averaged across 10 years of hourly climate data. Pick a date for a specific day.

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South PasadenaUnited States11:31 AM localChange location

Annual average

18.3°C

across all months

Warmest month

30.9°C

Aug average high

Coolest month

8.5°C

Jan average low

Annual rainfall

385mm

total per year

South Pasadena is typically hottest in August and coolest in January, a swing of about 22.4°C across the year. About 59% of annual rainfall falls in the three wettest months (January is typically wettest, July driest).

Monthly averages

Average daily high/low temperature (band) and monthly rainfall (bars).

JanFebMarAprMayJunJulAugSepOctNovDec
Avg high Avg low Rainfall
MonthAvg highAvg lowRainfallWet daysHumidityWindCloudSolar
Jan19°C · record 21.1–31.3°C8.5°C · record 2.6–5.8°C81mm663%1.8 m/s50%3.1 kWh/m²
Feb19.9°C · record 18.9–32°C8.9°C · record 2.1–7.3°C73mm658%1.9 m/s42%4.1 kWh/m²
Mar20.2°C · record 22.7–30.9°C10.1°C · record 4.6–8.1°C74mm865%1.9 m/s50%5.2 kWh/m²
Apr23°C · record 26.8–37.2°C12.2°C · record 4.7–10.4°C16mm260%2 m/s44%6.7 kWh/m²
May23.3°C · record 24.2–37.1°C14°C · record 8.8–12.7°C10mm266%2.1 m/s48%7.1 kWh/m²
Jun26.8°C · record 28.4–41.9°C16.3°C · record 12.7–14.8°C3mm164%2.1 m/s36%7.9 kWh/m²
Jul30.1°C · record 31.7–45°C18.5°C · record 15.1–17.2°C1mm062%2 m/s25%8 kWh/m²
Aug30.9°C · record 33.6–40°C19.1°C · record 15.3–18.3°C7mm161%1.9 m/s24%7.3 kWh/m²
Sep29.7°C · record 33.8–44.6°C18.2°C · record 11.8–17.1°C7mm161%1.7 m/s29%6 kWh/m²
Oct27.3°C · record 32.5–39.9°C15°C · record 8.1–13.1°C11mm256%1.6 m/s29%4.8 kWh/m²
Nov23.4°C · record 25.3–34.4°C11.2°C · record 5.1–9°C30mm353%1.6 m/s38%3.6 kWh/m²
Dec19.6°C · record 22.7–28.3°C8.9°C · record 2.6–7°C70mm560%1.7 m/s49%2.8 kWh/m²

"Avg high"/"Avg low" is the mean daily high/low for that month, averaged across every year on file. The "record" figure alongside it is a different statistic — the single hottest (or coldest) hour ever recorded during that month across all years — so it can sit above or below the average and does not describe the average's year-to-year spread. A "wet day" is any day with at least 1.0mm of rain.

Year to year

Annual average temperature, 2016–2025.

20162018202020222024

Across these 10 years, the annual average has moved by about -1.38°C per decade. That’s a short window for a reliable long-term climate trend — treat it as indicative, not definitive.

Annual rainfall has moved by about +216.91mm per decade over the same period.

2025 (the most recent year on file) averaged 17.990661802248347°C, below the 9-year baseline of 18.39°C by 0.7 standard deviations.

Typical extremes per year

Rainy days

35.7 days

≥1.0mm rain

Heavy rain days

5.1 days

≥20mm rain

Extreme heat days

1.3 days

daily high ≥40°C

Frost days

0 days

daily low ≤0°C

Averaged across 10 years on file. Thresholds match PastClimate's data pipeline definitions — see data & sources.

Records on file

Ranked across 10 years of data currently on file (2016–2025).

Hottest day

45°C

6 July 2018

2018 was 0.86 SD above the 9-year average that year

Coldest day

2.1°C

20 February 2018

2018 was 0.86 SD above the 9-year average that year

Wettest day

62.1mm

5 February 2024

2024 was 1.76 SD below the 9-year average that year

Windiest day

6.7m/s

24 February 2023

2023 was 1.8 SD below the 9-year average that year

See the detail: South Pasadena on 5 February 2024.

Frequently asked questions about South Pasadena's climate

What is the hottest month in South Pasadena?

August is typically the warmest month in South Pasadena, with an average high of 30.9°C. January is typically the coolest, averaging 8.5°C overnight.

How much does it rain in South Pasadena?

South Pasadena gets about 385mm of rain a year on average, with roughly 59% of it falling in the three wettest months (January is typically the wettest, July the driest).

How many extremely hot or cold days does South Pasadena have?

On average, South Pasadena sees about 1.3 day(s) a year at or above 40°C and about 0 day(s) at or below 0°C, based on 10 years of data.

Is South Pasadena getting warmer?

Across the 10 years on file (2016–2025), the annual average temperature has moved by about -1.38°C per decade. That's a short window for a reliable long-term climate trend — treat it as indicative, not definitive.

What is the hottest day on record for South Pasadena?

The hottest day on file is 6 July 2018 at 45°C, out of 10 year(s) searched.

Data & provenance

↓ Download monthly CSV
Data source & coverage — ERA5 reanalysis, 2016–2025 (10 years)details
Source
ERA5 reanalysis, accessed via the Copernicus Climate Change Service (C3S) Climate Data Store
Data type
Reanalysis — a physically consistent reconstruction combining a forecast model with historical observations, not a live station reading or a forecast
Coverage
2016–2025 (10 years) for United States
Location
South Pasadena — 34.000°, -118.250°, ERA5 grid cell center, 15.8 km from requested point
Time zone
America/Los_Angeles
What's shown here
Monthly and annual averages, and dated extreme-value records, derived from an hourly base record.
Spatial resolution
0.25° (~25 km) distributed grid — ERA5's native model resolution is finer; this is the publicly distributed regridded product
Version / refreshed
Methodology v2026.07 · data last refreshed December 31, 2025
Limitations
A model reconstruction, not a station observation — hyper-local extremes (a single storm cell, an urban heat pocket) can differ from a nearby gauge. See the full methodology.
Attribution
Generated using Copernicus Climate Change Service information

Cite this data

Plain text
PastClimate (2026-07-18). Historical climate data for South Pasadena, United States (34.00°N, 118.25°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
APA
PastClimate. (2026). Historical climate data for South Pasadena, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 18, 2026, from https://www.pastclimate.com/
MLA
"Historical Climate Data for South Pasadena, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 18, 2026, www.pastclimate.com.
BibTeX
@misc{pastclimate,
  author = {PastClimate},
  title = {Historical climate data for South Pasadena, United States},
  year = {2026},
  note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-18},
  url = {https://www.pastclimate.com/}
}

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