Hayward has warmed about 1.3°F between 1971 and 2020.
About 0.3°F per decade, measured from Hayward's official daily weather records, 1971–2020. Individual years still bounce around — some recent ones came in cool — but the long-term line has clearly risen.
Is that a lot? Hayward's climate has warmed more slowly 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
3 / yr
→
Recent
2 / yr
Milder winters — fewer frosts
Average temperature
+0.4°F
1970s
59.6°F
→
Recent
60.0°F
A steady upward drift
Hot days above 90°F
1 more day
1970s
8 / yr
→
Recent
9 / yr
More days of serious heat
Rainy days
about the same
1970s
59 / yr
→
Recent
57 / yr
Rainfall pattern about the same
Hayward's temperature, year by year
Average temperature for each year from 1971 to 2020.
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.
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.
December has warmed the most — about 0.7°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 Newark (NOAA GHCN station USC00046144), about 18 km from the city centre.