Photo: Mhsheikholeslami · CC BY-SA 4.0Summer arrives in force in Newmarket, hotter than in 91% of Canadian towns
Midwinter brings lows of about −10.1°C. Rain or snow is most frequent in June and least in February. Frost is rarer than in 70% of Canadian towns: about 145 nights a year drop below freezing. Ice scrapers and block heaters earn their keep on roughly 145 days a year at 0°C or below.
The nearest ECCC normals location to Newmarket is Toronto Buttonville (Airport), 23 km south, and every figure on this page is its.
A year in Newmarket at a glance
Each month’s typical high and low, in °C.
What stands out about Newmarket’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Newmarket feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
About 145 frosts and 126 warm days a year
The frost season runs October to May, and January freezes nearly every night. Deep cold, under −20°C, comes on about 6 nights a year.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
862 mm of precipitation in a typical year
On about 113 days a year, 1 mm or more falls.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
About 146 cm of snow a year
The snow season runs November to April; January brings the most, about 40 cm.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Newmarket
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
One degree below 18°C for one day makes one heating degree day; the year’s days are added together. Over a year, a home here needs less heating than 74% of Canadian towns.
Living with Newmarket’s climate
Gardening, time outside, winter cold and summer heat, from the 1991–2020 normals.
Frost usually lets go around 3 May and returns near 13 October, about 161 days apart.
Plan time outside for Jun, Aug and Sep: highs of 17–27°C and nights no colder than 8°C.
Parks & trails →Frostbite weather, a wind chill under −20, turns up on about 22 days a year.
About 55 days a year turn sultry, with the humidex past 30.
A normal year has no blizzard, flood or heat wave in it; Newmarket’s hazards page looks at those.
Flood & hazards →ECCC’s normals location: Toronto Buttonville (Airport)
Toronto Buttonville (Airport) is a composite: ECCC joins 3 stations’ readings to make its 1991–2020 normals.
| Distance from the town | 23 km south |
| Station altitude | 198 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Coldest reading, 1991–2020 | −35.2°C |
| Hottest reading, 1991–2020 | 37.8°C |
| Average wind | 12.2 km/h on average, most often from the north |
| Next-nearest location | Egbert, 32 km |
How Newmarket 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
Nearby places read from a different ECCC location (places on Newmarket’s own would show the same figures).
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Newmarket Toronto Buttonville (Airport) | 27.3°C | −10.1°C | 862 mm |
| Aurora 5.4 km · Toronto Buttonville (Airport) | 27.3°C about the same | −10.1°C about the same | 862 mm |
| East Gwillimbury 7.3 km · Udora | 26.3°C 1.0°C cooler | −11.7°C 1.6°C colder | 883 mm |
| Bradford 11 km · Egbert | 26.0°C 1.3°C cooler | −11.3°C 1.2°C colder | 793 mm |
Newmarket weather by month
Month by month, 1991–2020: the usual high, low and mean, the rain and snow, and the snowfall.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −1.7°C | −10.1°C | −6.0°C | 64 mm | 40 cm |
| February | −1.0°C | −10.1°C | −5.6°C | 51 mm | 34 cm |
| March | 4.6°C | −5.0°C | −0.2°C | 52 mm | 20 cm |
| April | 11.8°C | 1.2°C | 6.5°C | 79 mm | 7 cm |
| May | 19.3°C | 7.4°C | 13.4°C | 80 mm | under 1 cm |
| June | 24.6°C | 13.0°C | 18.8°C | 87 mm | 0 cm |
| July | 27.3°C | 15.6°C | 21.5°C | 85 mm | 0 cm |
| August | 26.3°C | 14.8°C | 20.6°C | 72 mm | 0 cm |
| September | 21.9°C | 10.4°C | 16.2°C | 83 mm | 0 cm |
| October | 14.3°C | 4.3°C | 9.4°C | 71 mm | 1 cm |
| November | 7.4°C | −0.8°C | 3.3°C | 77 mm | 12 cm |
| December | 1.5°C | −5.8°C | −2.2°C | 63 mm | 33 cm |
| Year | 13.0°C | 2.9°C | 8.0°C | 862 mm | 146 cm |
March: −25.6°C at its coldest, 26.3°C at its warmest
From one year to the next, January’s average typically shifts by 3.1°C around its normal of −6.0°C, the widest of any month, while June’s shifts by 1.2°C.
Where Newmarket’s numbers come from
Averages over 30 years, not a forecast.
- Normals: ECCC’s 1991–2020 Canadian Climate Normals for Toronto Buttonville (Airport), the nearest location with a full year of temperatures.
- Comparisons: the towns and neighbourhoods of 2,500+ across Canada, each on its nearest normals location, without the city totals or the reserves.
- Not on this page: hours of sunshine, missing from the 1991–2020 normals, and a height correction: the town has no elevation on file.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Newmarket’s climate
How warm does Newmarket get in summer?
Expect highs near 27.3°C in July, the hottest month on average.
How cold does Newmarket get in winter?
A typical January night falls to −10.1°C, the year’s low point.
How much rain and snow does Newmarket get?
Measured as water, a year brings 862 mm: 87 mm in June, the wettest month, and 51 mm in February, the driest.
How long does snow stay on the ground?
Snow cover of 1 cm or more lasts about 76 days in a typical year.
Are these figures for Newmarket itself?
No: Newmarket has no normals location, so the figures come from Toronto Buttonville (Airport), the nearest with 1991–2020 normals.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Newmarket →
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).