Hardly any Canadian towns see harsher January nights than Black River-Matheson
Peak summer warmth arrives in July, with afternoons near 24.0°C. Some 46°C separates winter nights from summer afternoons. By July afternoons alone, it runs cooler than 70% of Canadian towns. Homes need heating from October to April, the months averaging under 10°C.
Every figure here comes from Kirkland Lake, 51 km south-east; ECCC has no normals closer to Black River-Matheson, so they describe the wider area.
A year in Black River-Matheson at a glance
Each month’s typical high and low, in °C.
What stands out about Black River-Matheson’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Black River-Matheson feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
Frost on 192 days, 20°C on 87
The frost season runs September to May, and January freezes nearly every night. Some 54 nights a year drop under −20°C.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
787 mm of precipitation in a typical year
August is the wettest month and February the driest. 862nd wettest of 871 towns of 2,500+ in Ontario. Some 123 days a year see 1 mm of rain or snow or more.
Rain and snow by month
Millimetres
Snowfall: about 308 cm in a normal year
The snow season runs October to May; December brings the most, about 64 cm.
Snowfall by month
Centimetres
Kirkland Lake publishes no full year of snowfall, so these figures come from Timmins/Victor Power, 68 km away.
Heating a home in Black River-Matheson
90% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
Degree days add up how far each day’s mean temperature falls below 18°C over a year. Homes here need more heating than 94% of Canadian towns.
Living with Black River-Matheson’s climate
The averages read for the garden, the outdoors and the coldest and hottest days.
Tender plants are usually safe from around 25 May until frost returns near 25 September: about 123 days.
Mild days and mild nights together (17–27°C by day, 8°C or more at night) belong to Jun, Jul and Aug.
Parks & trails →A humidex above 30 marks about 23 days in a normal year.
For the weather that does damage, from ice storms to floods, see Black River-Matheson’s hazards page.
Flood & hazards →ECCC’s normals location: Kirkland Lake
Kirkland Lake is a composite: ECCC joins 2 stations’ readings to make its 1991–2020 normals.
| Distance from the town | 51 km south-east |
| Station altitude | 324 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Snowfall from | Timmins/Victor Power, 68 km |
| Coldest reading, 1991–2020 | −43.5°C |
| Hottest reading, 1991–2020 | 37.5°C |
| Next-nearest location | Timmins/Victor Power, 68 km |
How Black River-Matheson compares
Against the 2,611 Canadian towns and neighbourhoods of 2,500 or more, each read from its own normals location; the dots are the other locations those towns use in Ontario.
Nearby towns’ climate
The nearest places on a normals location of their own: those that share Black River-Matheson’s would only repeat its figures. The nearest place to Black River-Matheson with figures is 33 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Black River-Matheson Kirkland Lake | 24.0°C | −21.9°C | 787 mm |
| Iroquois Falls 33 km · Timmins/Victor Power | 24.4°C about the same | −22.3°C about the same | 796 mm |
Black River-Matheson weather by month
Each month’s normals, 1991–2020: high, low, mean, precipitation and snowfall.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −9.8°C | −21.9°C | −15.9°C | 47 mm | 59 cm |
| February | −7.6°C | −21.1°C | −14.5°C | 36 mm | 48 cm |
| March | −0.2°C | −14.2°C | −7.2°C | 43 mm | 43 cm |
| April | 7.0°C | −5.0°C | 1.0°C | 62 mm | 25 cm |
| May | 16.4°C | 4.0°C | 10.2°C | 65 mm | 3 cm |
| June | 21.9°C | 10.0°C | 15.9°C | 74 mm | under 1 cm |
| July | 24.0°C | 12.8°C | 18.4°C | 88 mm | 0 cm |
| August | 22.3°C | 11.7°C | 17.0°C | 90 mm | 0 cm |
| September | 17.5°C | 7.4°C | 12.5°C | 88 mm | 1 cm |
| October | 9.2°C | 1.4°C | 5.3°C | 78 mm | 14 cm |
| November | 1.0°C | −6.1°C | −2.6°C | 63 mm | 51 cm |
| December | −6.1°C | −15.5°C | −10.8°C | 54 mm | 64 cm |
| Year | 8.0°C | −3.1°C | 2.5°C | 787 mm | 308 cm |
January varies most from one year to the next (3.7°C), August least
Bars run from each month’s record low to its record high since 1991. March spans the most, from −39.4°C (2003) to 26.5°C (2012).
Where Black River-Matheson’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the Canadian Climate Normals, 1991–2020, at Kirkland Lake (the closest location with all twelve months of temperatures).
- Other locations: a location missing months of precipitation or snow is filled from the nearest that has them all, never mixed month by month.
- Comparisons: every place of 2,500+ in Canada but the city hubs and the reserves, each on its nearest ECCC location.
- Not on this page: sunshine, absent from every 1991–2020 location, and an altitude correction, for want of the town’s own elevation.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Black River-Matheson’s climate
How warm does Black River-Matheson get in summer?
Of all twelve months, July has the warmest afternoons, about 24.0°C.
How cold does Black River-Matheson get in winter?
January nights average −21.9°C, the coldest of the year.
How much rain and snow does Black River-Matheson get?
Some 787 mm falls in a year. Most of it comes in August (90 mm), the least in February (36 mm).
Are these figures for Black River-Matheson itself?
They are the figures for Kirkland Lake, which read better as the region’s climate than Black River-Matheson’s own.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Black River-Matheson →
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).