Nappan is a weather station located 20 m above sea level, 7 km from Amherst. Its records go back to 1914: 106 years of temperature are available up to 2020, along with rainfall and a comparison with two reference normals. Closed series: the records of this station end in 2020. Over 1991–2020 the annual mean temperature there is 6.3 °C, clearly higher than over 1961–1990 (5.5 °C): a difference of 0.8 °C. The warmest year of the series is 1999 (8.0 °C) and the coldest 1923 (4.1 °C). The last complete year, 2020, ranks 5 out of 106, from warmest to coldest. Over 1961–2020, the annual mean temperature changes by +0.23 °C per decade. The station ranks 129 out of 240 stations, from the fastest rise to the slowest.
Annual mean temperature since 1914
The first ten years of the series (1914–1923) average 4.8 °C; the last ten (2011–2020) average 6.3 °C, a difference of +1.5 °C. Of the ten warmest years in the series, 5 fall after 1999. The warmest is 1999 (8.0 °C). The ten-year running mean peaks at 6.6 °C (2007) and bottoms out at 4.8 °C (1926).
Annual rainfall since 1914
On average 1199 mm of rain falls per year over the 87 documented years. The wettest year, 1979, received 1815 mm; the driest, 1924, only 816 mm, which is 2.2 times less. Over 1961–1990, December is on average the wettest month (150 mm) and September the driest (89 mm). Between 1982 and 2002, 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 | −7.4 °C | −6.9 °C | +0.5 °C | 133 mm | – | – |
| February | −7.3 °C | −6.3 °C | +1.0 °C | 116 mm | – | – |
| March | −2.4 °C | −2.0 °C | +0.4 °C | 112 mm | – | – |
| April | 3.3 °C | 4.2 °C | +0.9 °C | 100 mm | – | – |
| May | 9.5 °C | 10.1 °C | +0.6 °C | 97 mm | – | – |
| June | 14.7 °C | 15.0 °C | +0.3 °C | 90 mm | – | – |
| July | 18.1 °C | 18.8 °C | +0.7 °C | 103 mm | – | – |
| August | 17.6 °C | 18.5 °C | +0.9 °C | 94 mm | – | – |
| September | 13.3 °C | 14.6 °C | +1.3 °C | 89 mm | – | – |
| October | 8.3 °C | 8.8 °C | +0.5 °C | 112 mm | – | – |
| November | 2.7 °C | 3.3 °C | +0.6 °C | 117 mm | – | – |
| December | −4.2 °C | −2.5 °C | +1.7 °C | 150 mm | – | – |
The largest temperature change is in December (+1.7 °C) and the smallest in June (+0.3 °C); over the year the mean difference is +0.8 °C, and 12 months out of twelve are warmer than before.
Records at Nappan
- Warmest year: 8.0 °C, in 1999
- Coldest year: 4.1 °C, in 1923
- Driest year: 816 mm, in 1924
- Wettest year: 1815 mm, in 1979
- Warmest month: 21.0 °C, in July 1947
- Coldest month: −13.9 °C, in January 1920
- Wettest month: 338 mm, in December 1990
3.9 °C separate the warmest year of the series from the coldest. Daily records are not part of the dataset for this station: only annual and monthly extremes are shown.
Temperature trend over 1961–2020
The regression line of annual mean temperature changes by +0.23 °C per decade between 1961 and 2020, about +1.4 °C over the whole period. That is slower than the median of the 240 stations (+0.25 °C per decade), by 0.02 °C per decade: the station ranks 129 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 Nappan 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 Nappan?
Over 1991–2020, the annual mean temperature at Nappan is 6.3 °C. It was 5.5 °C over 1961–1990, a difference of +0.8 °C.
What is the warmest year ever measured at Nappan?
Since records began in 1914, the warmest year at Nappan is 1999, at 8.0 °C on average. The coldest is 1923 (4.1 °C).
Is the climate at Nappan getting warmer?
Yes: at Nappan, the annual mean temperature rises by 0.23 °C per decade between 1961 and 2020, +1.4 °C in total. 5 of the 10 warmest years in the series fall after 1999.
Towns near this station
Neighbouring stations