Ottawa weather
Loading live data…Clear,warmer tomorrow
Env. Canada, the European and the American model put Ottawa's high today between 11° and 14°, a 3° split. Tomorrow: partly cloudy, around 16°, with a 1% chance of rain.
Latest for Ottawa: Env. Canada (GEM model): -1° Clear · European (ECMWF): 1° Clear · American (NOAA GFS): -3° Clear.
CheckWeather.io on iPhoneFree. No ads, no account.Ottawa weather in numbers
measured normals and 10 years of recorded weatherOttawa swings 39°C across the year, from 25°C highs in July to -14°C lows in February, and September is usually the wettest month in a year that brings about 960 mm of precipitation. Over 10 years of recorded weather it averages 62 days a year at 25°C or above, 12 of them at 30°C or above, 149 frost nights, and rain on 141 days.
Day counts are from the ERA5 reanalysis for Ottawa’s grid square, 2016 to 2025, counted the same way for every city so the numbers compare. A reanalysis square is an area, not a weather station, so it is good for counting days and not for a single day’s record.
The weather map: all three models at once
Env. Canada, European, American side by side around Ottawa and nearby towns.Live rain radar →Ottawa in 3D: the weather on the streets, hour by hour
Rain, sun and real shadows drawn on a 3D map of Ottawa, 48 hours ahead. Drag the timeline, pick what you are doing or where you are going, and read the verdict for that hour.Full screen ↗What are you doing?
Where are you going?
Ottawa hourly forecast: next 14 hours
consensus of the three modelsRain in the next 24 hours, model by model
each model's own hourly precipitation, side by sideLoading the three models…
Ottawa 10-day forecast, out to 14 days
where the models agree, and where they splitOttawa, Ontario. Below we compare what Env. Canada, European, American forecast for Ottawa right now and flag exactly where they disagree, then break down Ottawa's weather month by month and which forecast model has been most accurate here.
We grade every model against the weather that actually happened, so you can see which forecast model is most accurate in Canada before you trust any single number.
Ottawa weather by month
what to expect in Ottawa through the year, 1991-2020 averagesHere is Ottawa's typical weather in each month: the average daytime high and overnight low in °C, how each month feels, and the wettest month marked. Use it to plan any trip to Ottawa by season.
What Ottawa's weather is like through the year
Ottawa runs from warm summers, with July highs near 25°C, to cold winters, when February lows sit around -14°C (a swing of about 39°C across the year). September is usually the wettest month, and Ottawa sees roughly 960 mm of precipitation annually. Overnight lows stay below freezing across 6 months (January, February, March, April, November and December), so Ottawa sees regular winter snowfall.
Best time to visit Ottawa
The most comfortable time to visit Ottawa is usually May, June, July and August, when daytime highs sit in the pleasant 16-26°C range and the heaviest September rain is behind you.
How Ottawa's weather has changed since 1995
30 years of daily data, 1995-2024, shown as changeAround Ottawa, the difference between 1995-2004 and 2015-2024 is +0.8°C, within the normal swing from year to year.
Days above 30°C
2015-2024 against 1995-2004. Within the normal year-to-year swing
Frost nights
2015-2024 against 1995-2004, below 0°C. Within the normal year-to-year swing
Average wind
2015-2024 against 1995-2004. Within the normal year-to-year swing
Bars: each year against the area's 30-year average. Dashed lines: the average of the first and the last ten years.
See the numbers year by year
| Year | Temp vs average | Days >30°C vs avg | Frost nights vs avg | Wind vs avg |
|---|---|---|---|---|
| 1995 | −0.8°C | +2 | −0 | −0% |
| 1996 | −1.0°C | −6 | +16 | −0% |
| 1997 | −1.6°C | −2 | +10 | −0% |
| 1998 | +1.1°C | −3 | −10 | −0% |
| 1999 | +0.5°C | +5 | −2 | +4% |
| 2000 | −1.0°C | −6 | +5 | +4% |
| 2001 | +0.5°C | +3 | −4 | −0% |
| 2002 | +0.2°C | +3 | +15 | +4% |
| 2003 | −1.1°C | −2 | +5 | −0% |
| 2004 | −1.1°C | −6 | −0 | −0% |
| 2005 | +0.3°C | +4 | −7 | −0% |
| 2006 | +0.5°C | −0 | −10 | −0% |
| 2007 | −0.5°C | −2 | −4 | −0% |
| 2008 | −0.4°C | −4 | −2 | −0% |
| 2009 | −0.8°C | −3 | +1 | −4% |
| 2010 | +0.9°C | +7 | −7 | −0% |
| 2011 | +0.4°C | −5 | −7 | −4% |
| 2012 | +1.1°C | +11 | −3 | −0% |
| 2013 | −0.4°C | −1 | +5 | −0% |
| 2014 | −0.9°C | −5 | −1 | −0% |
| 2015 | −0.3°C | +2 | −4 | −0% |
| 2016 | +0.3°C | +4 | +5 | +4% |
| 2017 | ±0.0°C | −6 | −2 | −0% |
| 2018 | −0.2°C | +3 | +14 | −0% |
| 2019 | −1.1°C | −4 | +6 | +4% |
| 2020 | +0.5°C | +5 | +11 | −0% |
| 2021 | +1.2°C | +9 | −14 | −4% |
| 2022 | +0.2°C | −0 | +1 | −0% |
| 2023 | +1.0°C | +3 | −2 | −4% |
| 2024 | +1.9°C | +3 | −12 | −0% |
Source: NASA POWER daily data from the MERRA-2 reanalysis, 1995-2024. Each value describes a grid square of about 50 km around Ottawa, not a weather station, and a square that takes in sea or a large lake runs milder than the city itself. That is why this section shows change against the square's own 30-year average rather than counts you could compare with a local station. Rain and snow are left out because their long-term record in this dataset is not consistent over time. "Within the normal year-to-year swing" means the change is smaller than the usual differences between single years.
Which forecast is most accurate in Ottawa?
CheckWeather Score, graded against the weather that actually happened
The CheckWeather Score blends temperature, wind and rain accuracy, each measured against ERA5 (the recorded weather) over the last 30 days across 1320 cities. Lower error means a higher score. See which forecast model is most accurate in Canada, how we measure forecast accuracy, or which model each weather app uses.
Bottom line: over the last 30 days the European model has been the most accurate forecast for Ottawa, scoring 96/100 on our CheckWeather Score, ahead of the American at 86. See the full CA accuracy scoreboard for exactly how every model is tested.
What do you think of the forecasts?
your vote countsThe accuracy above is the measured record. This is your opinion: which forecast service do you trust most in Canada? Give each 1 to 5 stars.
One vote per service. Anonymous: we store no personal data, only a one-way hash of your connection for a day to stop double votes.
Where the models disagree
temperature and rain, judged separatelyThe models often agree on temperature and still split on rain, and rain is usually what decides whether a plan survives. A wide rain range means the shower is genuinely uncertain, not that the forecast is wrong.