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Has the climate in Cornwall changed?

Cornwall has warmed about 3.6°F between 1971 and 2020.

About 0.7°F per decade, measured from Cornwall'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? Cornwall's warming is broadly in line with other cities in Canada — neither unusually fast nor unusually slow.

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.

Average temperature
+2.6°F
1970s
44.4°F
Recent
47.0°F
A steady upward drift

Cornwall's temperature, year by year

Average temperature for each year from 1971 to 2020.

41°43°45°47°49°51°1971: 43.8°F1972: 42.2°F1973: 45.9°F1974: 43.6°F1975: 46.1°F1976: 42.7°F1977: 44.6°F1978: 43.1°F1979: 45.2°F1980: 43.2°F1981: 45.6°F1982: 44.3°F1983: 45.5°F1984: 45.2°F1985: 44.6°F1986: 44.9°F1987: 46.2°F1988: 45.9°F1989: 43.9°F1990: 47.0°F1991: 47.2°F1992: 43.6°F1993: 44.2°F1994: 44.8°F1995: 45.3°F1996: 45.3°F1997: 44.5°F1998: 48.9°F1999: 48.4°F2000: 45.4°F2001: 48.4°F2002: 47.5°F2003: 45.0°F2004: 44.5°F2005: 46.8°F2006: 48.0°F2007: 46.3°F2008: 46.0°F2009: 45.1°F2010: 48.3°F2011: 48.5°F2012: 49.1°F2013: 45.9°F2014: 45.4°F2015: 46.3°F2016: 48.1°F2017: 46.8°F2018: 46.4°F2019: 46.0°F2020: 48.4°Flong-term trend197119801990200020102020
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.

0.0°+0.5°+1.0°+1.5°+2.0°+2.5°+3.0°January: +1.8°F+1.8JFebruary: +1.5°F+1.5FMarch: +0.6°F+0.6MApril: +0.7°F+0.7AMay: +0.7°F+0.7MJune: +1.2°F+1.2JJuly: +1.1°F+1.1JAugust: +1.5°F+1.5ASeptember: +2.5°F+2.5SOctober: +1.5°F+1.5ONovember: +1.3°F+1.3NDecember: +2.6°F+2.6D

December has warmed the most — about 2.6°F. The warming runs across the whole year, not just one season.

Methodology & sources

Temperature — 1991–2020 normals computed from 30 years of daily observations at Cornwall, a weather station, about 2 km from the city centre. The underlying daily records come from NOAA's global station network.

How we build these numbers →