Chelsea is a weather station located 113 m above sea level, 2 km from Chelsea. Its records go back to 1928: 81 years of temperature are available up to 2019, along with rainfall and a comparison with two reference normals. Closed series: the records of this station end in 2019. Over 1991–2020 the annual mean temperature there is 6.1 °C, noticeably higher than over 1961–1990 (5.5 °C): a difference of 0.6 °C. The warmest year of the series is 2006 (7.3 °C) and the coldest 1934 (3.7 °C). The last complete year, 2019, ranks 47 out of 81, from warmest to coldest. Over 1961–2019, the annual mean temperature changes by +0.16 °C per decade. The station ranks 205 out of 240 stations, from the fastest rise to the slowest.
Annual mean temperature since 1928
The first ten years of the series (1928–1938) average 5.1 °C; the last ten (2005–2019) average 6.1 °C, a difference of +1.0 °C. Of the ten warmest years in the series, 4 fall after 1999. The warmest is 2006 (7.3 °C). The ten-year running mean peaks at 5.9 °C (1999) and bottoms out at 4.5 °C (1943).
Annual rainfall since 1928
On average 999 mm of rain falls per year over the 79 documented years. The wettest year, 2017, received 1400 mm; the driest, 1931, only 708 mm, which is 2.0 times less. The 1991–2020 normal (1036 mm per year) is 42 mm (4.2 %) above the 1961–1990 one (994 mm). Over 1991–2020, June is on average the wettest month (101 mm) and February the driest (70 mm). Between 1990 and 2017, 15 years out of 20 exceeded the series average.
Monthly normals: 1961–1990 against 1991–2020
The table compares, month by month, the mean temperature and the rainfall total of two thirty-year reference periods. The difference column shows what the recent period changes compared with the earlier one.
| Month | Temp. 1961–1990 | Temp. 1991–2020 | Difference | Rain 1961–1990 | Rain 1991–2020 | Difference |
|---|---|---|---|---|---|---|
| January | −11.6 °C | −10.5 °C | +1.1 °C | 74 mm | 84 mm | +10 mm |
| February | −10.1 °C | −8.7 °C | +1.4 °C | 68 mm | 70 mm | +2 mm |
| March | −3.4 °C | −3.0 °C | +0.4 °C | 67 mm | 75 mm | +8 mm |
| April | 5.0 °C | 5.4 °C | +0.4 °C | 70 mm | 83 mm | +13 mm |
| May | 12.5 °C | 12.8 °C | +0.3 °C | 81 mm | 84 mm | +3 mm |
| June | 17.6 °C | 18.5 °C | +0.9 °C | 89 mm | 101 mm | +12 mm |
| July | 20.5 °C | 20.9 °C | +0.4 °C | 91 mm | 96 mm | +5 mm |
| August | 19.2 °C | 19.5 °C | +0.3 °C | 93 mm | 88 mm | −5 mm |
| September | 14.4 °C | 15.1 °C | +0.7 °C | 88 mm | 93 mm | +5 mm |
| October | 8.0 °C | 8.2 °C | +0.2 °C | 80 mm | 92 mm | +12 mm |
| November | 1.2 °C | 1.2 °C | 0.0 °C | 93 mm | 80 mm | −13 mm |
| December | −7.9 °C | −6.4 °C | +1.5 °C | 100 mm | 90 mm | −10 mm |
The largest temperature change is in December (+1.5 °C) and the smallest in November (0.0 °C); over the year the mean difference is +0.6 °C, and 11 months out of twelve are warmer than before. For rainfall, the largest difference is in April (+13 mm) and the smallest in November (−13 mm).
Records at Chelsea
- Warmest year: 7.3 °C, in 2006
- Coldest year: 3.7 °C, in 1934
- Driest year: 708 mm, in 1931
- Wettest year: 1400 mm, in 2017
- Warmest month: 24.2 °C, in July 2020
- Coldest month: −20.7 °C, in February 1934
- Wettest month: 264 mm, in July 1899
- Hottest day: 37.2 °C, on 1 August 1975
- Coldest day: −41.1 °C, on 30 December 1933
- Heaviest rain in one day: 145.8 mm, on 23 June 2011
3.6 °C separate the warmest year of the series from the coldest. Between the hottest and the coldest day on record, the range reaches 78.3 °C.
Temperature trend over 1961–2019
The regression line of annual mean temperature changes by +0.16 °C per decade between 1961 and 2019, about +0.9 °C over the whole period. That is slower than the median of the 240 stations (+0.25 °C per decade), by 0.09 °C per decade: the station ranks 205 out of 240.
Data source and licence
Data source: Environment and Climate Change Canada (dataset “AHCCD (ahccd-monthly) + climate-daily”), licence Open Government Licence – Canada. Last updated: 29 October 2026.
The data for Chelsea are shown as the source publishes them; this site does not correct them. A year is kept only if at least eleven months of measurements are available, and a normal is computed only with at least twenty years of data out of its thirty. Temperatures are rounded to 0.1 °C and rainfall to the millimetre. The station is one of 240 stations in Canada: the overview page lets you compare them.
Frequently asked questions
What is the annual mean temperature at Chelsea?
Over 1991–2020, the annual mean temperature at Chelsea is 6.1 °C. It was 5.5 °C over 1961–1990, a difference of +0.6 °C.
What is the warmest year ever measured at Chelsea?
Since records began in 1928, the warmest year at Chelsea is 2006, at 7.3 °C on average. The coldest is 1934 (3.7 °C).
Is the climate at Chelsea getting warmer?
Yes: at Chelsea, the annual mean temperature rises by 0.16 °C per decade between 1961 and 2019, +0.9 °C in total. 4 of the 10 warmest years in the series fall after 1999.
Towns near this station
Neighbouring stations