St. Thomas weather
Loading live data…Clear,much the same tomorrow
Env. Canada, the European and the American model put St. Thomas's high today between 15° and 17°, a 3° split. Tomorrow: cloudy, around 17°, with a 0% chance of rain.
Latest for St. Thomas: Env. Canada (GEM model): 3° Clear · European (ECMWF): 4° Clear · American (NOAA GFS): 3° Clear.
CheckWeather.io on iPhoneFree. No ads, no account.St. Thomas weather in numbers
measured normals and 10 years of recorded weatherSt. Thomas swings 34°C across the year, from 25°C highs in July to -9°C lows in February, and November is usually the wettest month in a year that brings about 1037 mm of precipitation. Over 10 years of recorded weather it averages 65 days a year at 25°C or above, 4 of them at 30°C or above, 123 frost nights, and rain on 145 days.
Day counts are from the ERA5 reanalysis for St. Thomas’s grid square, 2016 to 2025, counted the same way for every city so the numbers compare. A reanalysis square is an area, not a weather station, so it is good for counting days and not for a single day’s record.
The weather map: all three models at once
Env. Canada, European, American side by side around St. Thomas and nearby towns.Live rain radar →St. Thomas hourly forecast: next 14 hours
consensus of the three modelsRain in the next 24 hours, model by model
each model's own hourly precipitation, side by sideLoading the three models…
St. Thomas 10-day forecast, out to 14 days
where the models agree, and where they splitSt. Thomas, Ontario is at its warmest in Jul (average highs near 25°C) and coldest in Feb (lows around -9°C), with roughly 1037 mm of precipitation across the year. Below, compare what Env. Canada, European, American forecast for St. Thomas right now, and see exactly where they disagree.
We grade every model against the weather that actually happened, so you can see which forecast model is most accurate in Canada before you trust any single number.
St. Thomas climate by month
average daytime high and overnight low across a typical year (1991-2020)Source: 1991-2020 averages, ERA5 for this place adjusted with NASA POWER.
How the weather around St. Thomas has changed since 1995
St. Thomas sits in the same roughly 50 km square of NASA's reanalysis as London. That square ran 1.1°C warmer in 2015-2024 than in 1995-2004. See the full 30-year picture on the London page.
Which forecast is most accurate in St. Thomas?
CheckWeather Score, graded against the weather that actually happened
The CheckWeather Score blends temperature, wind and rain accuracy, each measured against ERA5 (the recorded weather) over the last 30 days across 1320 cities. Lower error means a higher score. See which forecast model is most accurate in Canada, how we measure forecast accuracy, or which model each weather app uses.
What do you think of the forecasts?
your vote countsThe accuracy above is the measured record. This is your opinion: which forecast service do you trust most in Canada? Give each 1 to 5 stars.
One vote per service. Anonymous: we store no personal data, only a one-way hash of your connection for a day to stop double votes.
Where the models disagree
temperature and rain, judged separatelyThe models often agree on temperature and still split on rain, and rain is usually what decides whether a plan survives. A wide rain range means the shower is genuinely uncertain, not that the forecast is wrong.