Weather in Lethbridge in December

The month to avoid. December is the month most people should skip in Lethbridge. Highs sit at -1.3 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 12 of 12 — near the bottom of Lethbridge's year. August is the month that works, and the swing between the two is 61 points, which is a different holiday rather than a slightly better one.

Rain on 8 days, 0 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at -1.3 °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: 30 nights drop below freezing, so anything left outside stays frozen. Across the twenty years measured, the hottest December day reached 9.9 °C and the coldest night fell to -34.6 °C.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 45 mm against 14 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 27 mm average is a reasonable planning figure, not a promise.

Wind is light at 12.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 83%, which at -1.3 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

Temperatures hold steady either side: 4.6 °C in November, -1.3 here, -0.9 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of Lethbridge's year — 8.2 hours of daylight against 16.3 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

With no coast nearby, the year swings a fair way — 37 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage. At 907 m the air is thin enough to matter — sun that burns faster than the temperature suggests, and nights that cool off quickly.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

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

December in Lethbridge versus nearby

If Lethbridge is one option among several, the nearby comparison is worth making. Calgary is close enough to be a coin toss — within a degree on temperature, 3 days less rain. Banff is the weaker option in December — 4.8 °C cooler, 6 days more rain.

So: December is a compromise. August is 61 points better and is what Lethbridge 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 Lethbridge

See all twelve months in Lethbridge, or where else to go in December.