About 0.7°F per decade, measured from Pasadena's official daily weather records, 1971–2025. Individual years still bounce around — some recent ones came in cool — but the long-term line has clearly risen.
Is that a lot? Pasadena's climate has warmed faster than most other cities in United States.
What has actually changed
Each card compares the 1970s (the first ten years of the
record) with recent years (the last ten) — the same span
the headline and the chart use.
Freezing nights
1 fewer night
1970s
1 / yr
→
Recent
0 / yr
Milder winters — fewer frosts
Average temperature
+2.5°F
1970s
65.1°F
→
Recent
67.7°F
A steady upward drift
Hot days above 90°F
22 more days
1970s
60 / yr
→
Recent
82 / yr
More days of serious heat
Rainy days
about the same
1970s
43 / yr
→
Recent
44 / yr
Rainfall pattern about the same
Pasadena's temperature, year by year
Average temperature for each year from 1971 to 2025.
a warmer-than-average year a cooler-than-average year
Each bar is one year. Most recent years sit above the older ones.
Some recent years still came in cool — warming is a slope,
not a straight climb.
In day-to-day terms, that long-term shift shows up as about 7 more days above 90°F compared with the 1970s.
When in the year the change shows up
How much warmer each month is now than in the 1970s.
Useful if you garden or care about a particular season —
otherwise the headline above already has the answer.
September has warmed the most — about 1.3°F. The warming runs across the whole year, not just one season.
Methodology & sources
Temperature — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Pasadena (NOAA GHCN station USC00046719), inside the city.