Orono is a weather station located 84 m above sea level, 4 km from Oshawa. Its records go back to 1924: 92 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 8.5 °C, clearly higher than over 1961–1990 (7.3 °C): a difference of 1.2 °C. The warmest year of the series is 2012 (10.8 °C) and the coldest 1926 (5.6 °C). The last complete year, 2019, ranks 25 out of 92, from warmest to coldest. Over 1961–2019, the annual mean temperature changes by +0.36 °C per decade. The station ranks 29 out of 240 stations, from the fastest rise to the slowest.
Annual mean temperature since 1924
The first ten years of the series (1924–1933) average 7.0 °C; the last ten (2010–2019) average 8.9 °C, a difference of +1.8 °C. Of the ten warmest years in the series, 8 fall after 1999. The warmest is 2012 (10.8 °C). The ten-year running mean peaks at 8.9 °C (2019) and bottoms out at 6.9 °C (1931).
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 | −5.7 °C | −4.2 °C | +1.5 °C | – | – | – |
| February | −4.9 °C | −3.4 °C | +1.5 °C | – | – | – |
| March | 0.0 °C | 0.7 °C | +0.7 °C | – | – | – |
| April | 6.4 °C | 6.6 °C | +0.2 °C | – | – | – |
| May | 12.2 °C | 12.8 °C | +0.6 °C | – | – | – |
| June | 16.9 °C | 18.1 °C | +1.2 °C | – | – | – |
| July | 19.8 °C | 20.8 °C | +1.0 °C | – | – | – |
| August | 18.8 °C | 20.3 °C | +1.5 °C | – | – | – |
| September | 14.7 °C | 16.6 °C | +1.9 °C | – | – | – |
| October | 8.9 °C | 10.2 °C | +1.3 °C | – | – | – |
| November | 3.6 °C | 4.3 °C | +0.7 °C | – | – | – |
| December | −2.7 °C | −0.9 °C | +1.8 °C | – | – | – |
The largest temperature change is in September (+1.9 °C) and the smallest in April (+0.2 °C); over the year the mean difference is +1.2 °C, and 12 months out of twelve are warmer than before.
Records at Orono
- Warmest year: 10.8 °C, in 2012
- Coldest year: 5.6 °C, in 1926
- Warmest month: 23.3 °C, in July 2018
- Coldest month: −12.7 °C, in February 1934
- Hottest day: 37.5 °C, on 21 July 2011
- Coldest day: −30.5 °C, on 4 January 1981
- Heaviest rain in one day: 144.8 mm, on 27 June 1971
5.2 °C separate the warmest year of the series from the coldest. Between the hottest and the coldest day on record, the range reaches 68.0 °C.
Temperature trend over 1961–2019
The regression line of annual mean temperature changes by +0.36 °C per decade between 1961 and 2019, about +2.1 °C over the whole period. That is faster than the median of the 240 stations (+0.25 °C per decade), by 0.11 °C per decade: the station ranks 29 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 Orono 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 Orono?
Over 1991–2020, the annual mean temperature at Orono is 8.5 °C. It was 7.3 °C over 1961–1990, a difference of +1.2 °C.
What is the warmest year ever measured at Orono?
Since records began in 1924, the warmest year at Orono is 2012, at 10.8 °C on average. The coldest is 1926 (5.6 °C).
Is the climate at Orono getting warmer?
Yes: at Orono, the annual mean temperature rises by 0.36 °C per decade between 1961 and 2019, +2.1 °C in total. 8 of the 10 warmest years in the series fall after 1999.
Towns near this station
Neighbouring stations