Travel time: Year-round
Banff’s climate is defined by its high elevation (1,383m/4,537ft) and its position on the eastern slopes of the Canadian Rockies. This creates a subarctic environment where weather can transition from brilliant sunshine to a heavy snowstorm in a matter of minutes.
In Banff, the most consistent feature of the day is the temperature swing. Due to the thin, dry air and high altitude, the "diurnal range" is extreme. Even in the height of summer, temperatures can plummet from a comfortable 22°C (72°F) during the day to just above freezing shortly after sunset. Locals live by the rule that the sun’s presence dictates the temperature; once it dips behind a peak, the air cools instantly.
Winter is the longest season, characterized by deep snow and cold, dry air. January is typically the coldest month, with average lows of -15°C (5°F), though "cold snaps" can push temperatures below -30°C (-22°F). Despite the cold, the sun often shines, creating "bluebird" days. The air is exceptionally dry, which makes the cold feel less piercing than damp coastal climates, but it also means static electricity and dry skin are common.
Spring in the Rockies is a slow transition. While the valley floor may see grass and wildflowers by May, the mountain peaks remain in full winter conditions. This is the season of "spring skiing," where you can experience sub-zero temperatures at the summit and double-digit warmth in town on the same afternoon. Many of the iconic turquoise lakes, such as Lake Louise and Moraine Lake, remain frozen until late May or early June.
Summer is mild and pleasant, with average highs of 22°C (72°F). July is the sunniest and warmest month. However, June is statistically the wettest month of the year, known for afternoon thunderstorms that roll in quickly and dissipate just as fast. The sun stays up late, with daylight lasting until 10:00 PM in late June, providing ample time for the mountain air to warm up.
Fall is short and dramatic. September brings the "Larch season," a fleeting period where subalpine conifers turn brilliant gold. Temperatures begin to drop sharply in October, with the first significant valley snowfalls typically occurring by the end of the month. Mornings are often frosty, leading into crisp, clear afternoons.
A crucial rule for the region is the Lapse Rate: temperatures typically drop about 1°C for every 200 meters of elevation gain. This means that while it may be raining in the Town of Banff, it is likely snowing at the top of the gondola or at the ski resorts. Localized weather can also vary between the Town of Banff and Lake Louise (which sits 200m higher and is consistently 3-5°C colder).