Weather in Barrie in September

Prime time. If you get to pick your dates, September is the one. Highs average 21.9 °C, lows 12.4 °C, and rain falls on 11 days — nothing in the month is working against you.

September ranks 4 of 12 in Barrie: past the worst of the year but short of August, which is the month to book if the dates are open.

Rain on 11 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest September day reached 32.9 °C and the coldest night fell to 3.3 °C.

September is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest September on record still delivered 77 mm against 28 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 51 mm average is a reasonable planning figure, not a promise.

Wind is light at 5.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 71%.

How September sits in the year

The month is on the way down: 3.6 °C cooler than August, with October dropping another 8.4 °C. The first week and the last are not the same trip.

Daylight in September

12.6 hours of daylight, losing 1.5 hours across the month. That is between Barrie's extremes of 15.5 and 8.9 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 36.4 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Barrie versus nearby

If Barrie is one option among several, the nearby comparison is worth making. Toronto is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Peterborough is close enough to be a coin toss — within a degree on temperature, 2 days less rain.

So: September is effectively as good as it gets here — 2 points behind August, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Barrie

See all twelve months in Barrie, or where else to go in September.