2021 Long Range Weather Forecast for Trenton, ON

Get the Long Range Weather for Your Location

See long range weather forecasts for the next 60 days from The Old Farmer’s Almanac! Our long range forecasts can be used to make more informed decisions about future plans that depend on the weather, from vacations and weddings to sporting events and outdoor activities.

To see long term forecasts for the entire year, pick up a copy of The 2021 Old Farmer’s Almanac, available online and in stores.

Note: Long range forecasts are regional, not city-specific.

Free 2-Month Weather Forecast

March 2021 Long Range Weather Forecast for Southern Ontario
DatesWeather Conditions
Mar 1-5Flurries, cold
Mar 6-12Snowstorm, then flurries, cold
Mar 13-15Sunny, mild
Mar 16-21Rainy periods, mild east; snow west
Mar 22-26Showers, mild
Mar 27-31Sunny, mild
Marchtemperature 0°C (avg.)
precipitation 75mm (20mm above avg.)

April 2021 Long Range Weather Forecast for Southern Ontario
DatesWeather Conditions
Apr 1-6A few showers, cool
Apr 7-13Scattered t-storms, warm
Apr 14-18Showers, turning cool
Apr 19-23Snow, then sunny, cool
Apr 24-30Rainy periods, cool
Apriltemperature 7.5°C (0.5°C above avg.)
precipitation 90mm (50mm above avg. east, avg. west)

Annual Weather Summary
November 2020 to October 2021

Winter temperatures will be slightly below normal in the east and slightly above normal in the west, with the coldest periods in early to mid-December, from late December into early January, and in mid- and late January. Precipitation and snowfall will be much above normal, with the snowiest periods in mid-December, early to mid-January, and early to mid-March. April and May will be cooler and rainier than normal in the east and warmer and drier in the west. Summer will be slightly cooler and rainier than normal in the east and hotter with near-normal rainfall in the west. The hottest periods will be in early June and mid-August. September and October will be cooler than normal, with near-normal precipitation.

Map showing Old Farmer's Almanac long range weather region number 3

About the Southern Ontario Region

The Southern Ontario long range weather region includes all or part of the following provinces: ONTARIO (Alliston, Amherstburg, Barrie, Bolton, Bradford, Brantford, Chatham, Cobourg, Collingwood, Elliot Lake, Fergus, Fort Erie, Georgetown, Guelph, Haileybury, Hamilton, Ingersoll, Kenora, Kitchener, Leamington, Lindsay, London, Midland, Milton, North Bay, Orangeville, Orillia, Oshawa, Owen Sound, Paris, Peterborough, Port Hope, Sarnia, Simcoe, Stouffville, Stratford, Strathroy, Sudbury, Thunder Bay, Tillsonburg, Timmins, Toronto, Uxbridge, Wallaceburg, Windsor, Woodstock).

Southern Ontario Neighboring Regions

Here are the regions that neighbor the Southern Ontario long range weather region:

Temperature and Precipitation November 2020 to October 2021

Temperature and Precipitation Chart, November 2020 to October 2021 for Trenton, ON

Reader Comments

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Thunder Bay blackflies

I live in Thunder Bay. To be honest with you, last summer was so dry there were next to no blackflies in the summer. Blackflies breed in shallow creek beds left by rain or significant snow melt. We did not get much snow this year comparatively. Lakes will be low again this year too. You will need to worry more about the mosquitoes than blackflies. Late June or early July is best. The dragonflies are out and they love eating both!

Thunder Bay Forecast

I live in Thunder Bay and our weather is much different than Southern Ontario's weather. We are always a lot colder where I live and our January this year set some records for being warmer than normal. February on the other hand brought some real frigid temperatures {-40's} which might have also set some records. I also agree that we shouldn't be grouped in with Southern Ontario as their temps. are usually warmer.

Summer Holidays

I am trying to decide the best time for a two-week “camp” rental near Thunder Bay this summer. Your forecast predicts June having above normal temps but that’s the worst black fly season. What weeks might you suggest in July? Thanks, friends swear by this Almanac.

Ontario forecast (northwestern)

When giving forecasts for the Thunder Bay Area you can’t lump us together with southern Ontario. The farthest to the south you can include with Thunder Bay Area would be Terrace bay or at the most marathon, All though it’s usually warmer in marathon then any other area around the top of superior. Maybe look at updating the long rage forecasts in smaller zones for the future.

That spring feeling!

Hi there, I’m live 45 minutes north of Toronto and I am so done with winter! I can’t wait to get back into my garden. I was wondering, when can we expect to start feeling that spring weather? When the sun feels warmer, we can see the grass again, and the birds are singing!

prediction for weather


the good ol farmers of Ontario !!

Bless the warm hearts of all our Canadian farmers bust more so the good ol boys of Ottawa valley puttin in long hours of hard work so absorbed nothing on their minds but hard work to bring food to fork not even caring as to all that meadow muffin blues they got stuck on the bottom of they shoes trackin it all through town smellin up the whole place poor mildred stepped in some and slipped and broke her hip bone the poor ol lady is like a saint in these parts now she smells like a barnyard and has a broken hip !! I think we needs to pull together here as a community and reminds our good ol BOYs to please check they bottoms of they shoes for those meadow muffins we cant be havin no more blues

Any Blizzard or bad storm due in Jan or Feb?

I want to book a week off work in Jan or Feb, especially if there will be a big dumping of snow; so then I can avoid the drive to work. So, what week looks good for a potential stay at home week? (I live in the north Toronto GTA)


The Editors's picture

Hi, Ann Marie: While there will be plenty of snowy periods in January and February, the only “snowtime” that really stands out for us right now is the first week of January. It’s hard to say whether this will be a sustained dumping, though! Thanks for asking and have a nice week off, whenever it is!

What is considered Southern

What is considered Southern Ontario region is the problem for many. The weather in Windsor and Barrie are 2 different worlds. For instance, Barrie might get a foot of snow, while in Windsor-Essex at the same time, it could be sunny and 50F degrees.