Thunder Bay Snowfall Totals & Accumulation Averages

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This page pulls together information on when, how much and how often Thunder Bay, Ontario has snow.

There are data and descriptions here of how many days it snows and the total amount of snowfall that Thunder Bay usually gets. There are also monthly and yearly counts of the days that Thunder Bay 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 at the Thunder Bay International Airport.

How Often it Snows in Thunder Bay

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).

Average total snowfall and days with fresh snow in Thunder Bay
Days   Inches Centimetres
12.9 January 14.4   36
  9.6 February   8.3   21
  8.4 March   7.2   18
  4.0 April   4.0   10
  0.5 May   0.4     1
  0.3 September   0.4     1
  3.4 October   3.7     9
  9.7 November 10.4   26
13.9 December 15.3   39
62.5 Year 64.1 163

When Thunder Bay Has Its First & Last Snowfalls

The first snowfall of winter for Thunder Bay usually arrives in October, but can show up as early as September.

The season's last snowfall typically happens in April although in some years a late snow lands in May.

Thunder Bay is normally free of snow every year from June to August.

How Many Snowstorms Thunder Bay Gets

Most days of snowfall in Thunder Bay leave less than five centimetres (2 inches) of fresh snow on the ground. For ten 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 three or four times a year. But major blizzards that dump 25 cm or more in one day are rare events that happen just once a decade. Storms this severe are most likely to appear in January.

Number of days per month and year on average in Thunder Bay with a total snowfall of at least 5, 10 or 20 centimetres
  5 cm
2.0 inches
10 cm
3.9 inches
25 cm
9.8 inches
January 2.1 0.9 0.1
February 1.2 0.4 0.0
March 1.1 0.2 0.0
April 0.5 0.2 0.0
May 0.1 0.0 0.0
September 0.1 0.0 0.0
October 0.6 0.2 0.0
November 1.6 0.6 0.0
December 2.7 1.0 0.0
Year 9.9 3.5 0.1

How Much Snow Normally Accumulates in Thunder Bay

For about 127 days a year, Thunder Bay has at least a centimetre of snow on the ground. In mid-winter the snowpack averages around 29 cm deep.

Average total days per month and year in Thunder Bay with snow depth of at least 1, 5, 10 or 20 cm on the ground
1 cm
0.4 inches
5 cm
2.0 inches
  10 cm
3.9 inches
20 cm
7.9 inches
  29.1   27.6 January 25.8 23.3
  28.2   28.2 February 26.6 19.2
  26.1   21.2 March 14.9   9.9
    5.0     2.5 April   2.0   1.3
    0.1     0.0 May   0.0   0.0
    1.1     0.1 October   0.0   0.0
  11.9     4.2 November   2.6   0.9
  24.9   19.1 December 14.5 10.5
126.5 102.7 Year 86.4 65.0
Reference

Environment Canada. Meteorological Service of Canada. Canadian Climate Normals. 1981-2010 Climate Normals & Averages.

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