Ottawa Snowfall Totals & Accumulation Averages
This page pulls together information on when, how much and how often Ottawa, Ontario has snow.
There are data and descriptions here of how many days it snows and the total amount of snowfall that Ottawa usually gets. There are also monthly and yearly counts of the days that Ottawa normally has heavy snowstorms and deep snow accumulated on the ground. Plus there's information on when the city can expect its first and last snowfalls of the season.
All the numbers are long-term historical averages based on weather data gathered from 1981 to 2010 near downtown Ottawa.
How Often it Snows in Ottawa
This first table lists monthly and yearly totals for amount of snow and how many days it snows at least 0.2 centimetres (0.08 inches).
When Ottawa Has Its First & Last Snowfalls
The first snowfall of winter for Ottawa usually arrives in November, but can show up as early as October. A freak snow flurry in September has appeared, but the snow quickly melted.
The season's last snowfall typically happens in April although in some years a late skiff or even a dump of snow lands in May.
Ottawa is normally free of snow every year from June to August.
How Many Snowstorms Ottawa Gets
Most days of snowfall in Ottawa leave less than five centimetres (2 inches), of fresh snow on the ground. For 12 days a year on average, the amount of new snow totals at least five cm.
Big snowstorms of over ten cm a day normally occur about three or four times a year. But major blizzards that dump 25 cm or more in one day are rare events that happen once a decade.
How Much Snow Normally Accumulates in Ottawa
For about 115 days a year, Ottawa has at least a centimetre of snow on the ground. In mid-winter the snowpack averages from 21 cm deep.
Generally the snow cover begins to build in December and remains deep throughout most of January and February.
Environment Canada. Meteorological Service of Canada. Canadian Climate Normals. 1981-2010 Climate Normals & Averages.
Environment Canada. National Climate Data and Information Archive. Canadian Climate Normals or Averages 1971-2000.