Weather in Ottawa in October

Shoulder season. October is shoulder season in Ottawa — cheaper, quieter, and a genuine gamble. Highs sit at 13.5 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

October ranks 6 of 12 in Ottawa: past the worst of the year but short of September, which is the month to book if the dates are open.

Rain on 14 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 13.5 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 6 nights fall below freezing. Across the twenty years measured, the hottest October day reached 27.4 °C and the coldest night fell to -5.5 °C, and the wettest single day dropped 47 mm — roughly 47% of the month's rain in one day.

October is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest October on record still delivered 160 mm against 57 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 99 mm average is a reasonable planning figure, not a promise.

Wind is light at 1.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 81%, which at 13.5 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How October sits in the year

The month is on the way down: 8.4 °C cooler than September, with November dropping another 7.9 °C. The first week and the last are not the same trip.

Daylight in October

11 hours of daylight, losing 1.5 hours across the month. That is between Ottawa's extremes of 15.6 and 8.8 hours, so days are long enough not to constrain the plan.

An inland climate

Ottawa has no sea to moderate it, and it shows: 42.4 °C separates the hottest afternoon of the year from the coldest night. That is a genuinely continental range, and it means summer and winter here are barely the same place.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself.

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

October in Ottawa versus nearby

If Ottawa is one option among several, the nearby comparison is worth making. Kingston is close enough to be a coin toss — within a degree on temperature, 3 days more rain. Montréal is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: October is a compromise. September is 24 points better and is what Ottawa is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Ottawa

See all twelve months in Ottawa, or where else to go in October.