Photo: davestew89 · CC BY 3.0Few Canadian towns have colder winter nights than Marathon
July afternoons average 23.6°C. Rain or snow is most frequent in July and least in February. Summers stay cool: July afternoons here are cooler than in 72% of Canadian towns. Windshields need scraping on about 214 mornings a year, the days the air reaches 0°C or below.
Every figure here comes from Geraldton, 125 km north; ECCC has no normals closer to Marathon, so they describe the wider area.
A year in Marathon at a glance
Each month’s typical high and low, in °C.
What stands out about Marathon’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Marathon feels like
Seasons and months as ECCC’s 1991–2020 normals give them: a typical day’s high and low.
Frost on 214 days, 20°C on 83
The frost season runs September to May, and January freezes nearly every night. Some 71 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
762 mm of precipitation in a typical year
865th wettest of 871 towns of 2,500+ in Ontario. About 114 days a year bring 1 mm or more.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
Heating a home in Marathon
88% of a year’s heating need falls between October and April. Months averaging under 10°C: October to May.
ECCC sums, over the year, how many degrees each day’s average falls short of 18°C. In heating terms, homes need more heating than almost every Canadian town.
Living with Marathon’s climate
Gardening, time outside, winter cold and summer heat, from the 1991–2020 normals.
Gardens get from about 31 May to 16 September without frost, around 106 days in all.
Highs of 17–27°C with nights of 8°C or more come in Jun, Jul and Aug.
Parks & trails →On some 90 days a year the wind chill drops past −20; mitts and a scarf earn their place.
A humidex above 30 marks about 17 days in a normal year.
Thirty years of averages say little about one bad storm; Marathon’s hazards page does.
Flood & hazards →ECCC’s normals location: Geraldton
Behind the 1991–2020 normals for Geraldton are 2 stations, which ECCC combines into one record.
| Distance from the town | 125 km north |
| Station altitude | 348 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Snowfall from | No location within 100 km |
| Coldest reading, 1991–2020 | −50.2°C |
| Hottest reading, 1991–2020 | 37.0°C |
| Average wind | 11.4 km/h on average, most often from the west |
| Next-nearest location | Wawa, 143 km |
How Marathon compares
Placed among 2,611 Canadian towns and neighbourhoods of 2,500+, each on its nearest normals location; each dot is another location used in Ontario.
Nearby towns’ climate
Places around Marathon whose figures come from another normals location. The nearest places to Marathon with figures are 129–143 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Marathon Geraldton | 23.6°C | −24.7°C | 762 mm |
| Hornepayne 129 km · Wawa | 20.8°C 2.8°C cooler | −19.6°C 5.1°C milder | 967 mm |
| Nipigon 143 km · Thunder Bay | 24.9°C 1.3°C warmer | −19.2°C 5.5°C milder | 762 mm |
Marathon weather by month
Average daily high and low, mean temperature and precipitation by month, 1991–2020.
| Month | High | Low | Mean | Rain & snow |
|---|---|---|---|---|
| January | −12.2°C | −24.7°C | −18.5°C | 36 mm |
| February | −8.8°C | −23.4°C | −16.1°C | 26 mm |
| March | −1.3°C | −16.1°C | −8.7°C | 33 mm |
| April | 6.6°C | −6.7°C | 0.0°C | 49 mm |
| May | 15.2°C | 1.6°C | 8.4°C | 78 mm |
| June | 21.4°C | 8.0°C | 14.7°C | 82 mm |
| July | 23.6°C | 11.1°C | 17.4°C | 108 mm |
| August | 22.3°C | 9.9°C | 16.1°C | 76 mm |
| September | 16.5°C | 5.2°C | 10.9°C | 102 mm |
| October | 7.6°C | −0.8°C | 3.4°C | 84 mm |
| November | −1.0°C | −9.3°C | −5.1°C | 53 mm |
| December | −8.3°C | −18.3°C | −13.3°C | 37 mm |
| Year | 6.8°C | −5.3°C | 0.8°C | 762 mm |
March has run from −40.0°C to 20.7°C in thirty years
From one year to the next, February’s average typically shifts by 3.7°C around its normal of −16.1°C, the widest of any month, while August’s shifts by 1.3°C.
Where Marathon’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the 1991–2020 normals from ECCC for Geraldton, its nearest location with complete temperatures.
- 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: snow, with no complete snowfall normals within 100 km, sunshine, which ECCC published for no location, and any height adjustment.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Marathon’s climate
How warm does Marathon get in summer?
Midsummer means July, with afternoons near 23.6°C on a typical day.
How cold does Marathon get in winter?
Lows sink to −24.7°C on an average January night.
How much rain and snow does Marathon get?
Some 762 mm falls in a year. Most of it comes in July (108 mm), the least in February (26 mm).
Are these figures for Marathon itself?
No: they come from Geraldton, the nearest ECCC normals location, and far enough away to describe the wider area more than Marathon.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Marathon →
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).