Ontario

Clarence-Rockland, Canada Climate

NASA POWER reanalysis for the half-degree grid cell around Clarence-Rockland, 1991-2020; a grid cell is an area average and can differ from a thermometer in town by several degrees

The warmest month is July, with an average high of 25°C; the coldest is January, with an average low of -17°C. A normal year brings 978 mm of precipitation.

Temperature through the year

The normal daily high and low. The line marks today.

Normal daily high and low temperature at Clarence-Rockland through the year, in °C, with the record for each date.-60-40-2002040JanFebMarAprMayJunJulAugSepOctNovDec
  • Normal low
  • Normal high
  • Reanalysis extreme high
  • Reanalysis extreme low

Normals for Sep 25

Normal high
19°C
Normal low
8°C
Reanalysis high
29°Cin 2017
Reanalysis low
0°Cin 2000
Chance of a wet day
43%
Daylight
12 h 01 min

Month by month

Averages for 1991-2020. Wet days have at least 1 mm of precipitation in the reanalysis. Each month links to its own page.

MonthAvg highAvg lowWarmestColdestPrecipitationWet days
January-7°C-17°C11°C (2008)-42°C (1994)71 mm12.4
February-5°C-16°C14°C (2000)-38°C (2003)57 mm11.3
March1°C-9°C25°C (2012)-31°C (2007)68 mm12.4
April11°C-1°C27°C (2002)-14°C (2016)84 mm12.0
May18°C6°C31°C (2010)-4°C (2020)84 mm12.4
June23°C12°C33°C (2005)1°C (2009)102 mm15.0
July25°C15°C36°C (2018)7°C (1992)99 mm15.5
August25°C14°C34°C (2002)6°C (2004)84 mm12.4
September21°C10°C33°C (2002)-2°C (1991)87 mm12.0
October13°C3°C27°C (2018)-7°C (1997)93 mm12.4
November5°C-3°C20°C (2020)-21°C (1995)75 mm12.0
December-3°C-11°C17°C (2015)-45°C (1993)74 mm12.4
Year11°C0°C978 mm152

Precipitation

Rain and melted snow together. The chance of a wet day is the share of days with at least 1 mm of precipitation in the reanalysis.

978 mm in a normal year, most in June.

Chance of a wet day

The chance of at least 1 mm of precipitation in the reanalysis on each date at Clarence-Rockland, in percent.0204060JanFebMarAprMayJunJulAugSepOctNovDec
  • Chance of a wet day

Humidity and comfort

NASA POWER reanalysis, 1991-2020, for the grid cell around Clarence-Rockland.

The muggiest month is July, when 26 percent of days are muggy or worse, with a mean dew point of 18°C or more.

MonthDew pointHumidityDryComfortableHumidMuggyOppressiveMiserable
January-13°C95%100%0%0%0%0%0%
February-11°C95%100%0%0%0%0%0%
March-6°C88%100%0%0%0%0%0%
April1°C78%99%1%0%0%0%0%
May8°C77%83%10%5%2%0%0%
June14°C78%43%25%20%10%2%0%
July16°C79%15%29%31%20%6%0%
August15°C78%28%28%28%15%1%0%
September11°C78%65%20%10%5%0%0%
October4°C81%96%3%1%0%0%0%
November-2°C85%100%0%0%0%0%0%
December-8°C93%100%0%0%0%0%0%

Comfort is judged by the day's mean dew point: dry below 13°C, comfortable to 16°C, humid to 18°C, muggy to 21°C, oppressive to 24°C, miserable above.

Clouds

Average share of the sky covered, from satellite (CERES and GEWEX SRB) by way of NASA POWER, 1991-2020.

The clearest month is August, with the sky 58 percent covered on average; the cloudiest is December, at 73 percent.

Wind

The mean wind speed over the whole day, from the MERRA-2 reanalysis by way of NASA POWER. Gusts run well above it.

The windiest month is February, averaging 12.2 km/h at 10 meters (33 feet) above the ground.

Daylight and sunshine

The longest day is Jun 20, with 15 h 42 min of daylight; the shortest is Dec 16, with 8 h 42 min.

Hours of daylight at Clarence-Rockland through the year.0510152025JanFebMarAprMayJunJulAugSepOctNovDec
  • Day length

Solar energy

Average daily sunshine reaching the ground on a flat surface, in kilowatt-hours per square meter, clouds included.

Sunrise and sunset calendar

Month pages

The weather in Clarence-Rockland in each month, day by day.

What this means

A normal is the average of the thirty years 1991 to 2020, the period the World Meteorological Organization and NOAA use for comparison. It is an average, not a forecast: most days depart from it, and some by a long way.

Where no station record is within reach, the extremes shown are the highest and lowest the reanalysis produced for the date in 1991-2020, not measured records.

Cloud, humidity, wind and sunshine come from a reanalysis: a weather model run over the past with every observation fed in, averaged over a grid cell about 50 km across. It is consistent everywhere on Earth; it smooths local detail such as a lake shore or a valley.

More for this place

Nearby

Sources

Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.