Hail season in Calgary runs with the summer thunderstorm season — broadly June through early September, with July the peak. It is not spread evenly through the day: the storms that produce damaging hail here usually build over the foothills through the afternoon and track across the city between roughly mid-afternoon and early evening. A clear, hot, humid morning in July is exactly the setup that produces a 4pm hail warning.
Calgary sits at the north end of what insurers and meteorologists call Hailstorm Alley — a corridor along the Alberta foothills between roughly High River and Red Deer. Warm, moist air moving up from the prairies meets the elevation and cooler air coming off the Rockies, which drives the strong updrafts hail needs. The same storm that would produce plain rain further east gets the vertical lift here to keep cycling hailstones until they are big enough to fall.
The consequence is financial as well as meteorological: the June 2020 Calgary hailstorm became one of the costliest insured weather events in Canadian history, with losses measured in the billions, and the damage was heavily concentrated in the city's northeast.
The northeasthas taken the worst of Calgary's recent major hail events. Storms generally track from the southwest or south toward the northeast, and by the time a cell crosses the city it has often reached its most intense stage over the northeast quadrant. Being flatter and lower than the west side, the northeast also has less to disrupt an organised storm.
That does not make anywhere in the city safe — hail is famously narrow. A single storm can put golf-ball hail down one side of a street and leave the next community untouched, which is exactly why a single city-wide forecast is close to useless for deciding whether to move your car. Airdrie and the towns north of Calgary sit well inside the same corridor.
This site grades hail possibility for the next ~12 hours for each part of the city, from None through Severe, using the model's convective available potential energy (CAPE), precipitation type and probability. When a storm is genuinely imminent — within about 30 minutes — the map shows an alert banner for the affected districts. Open the live map and click your own community rather than relying on the city-wide number.
One important caveat: what you see here is a model forecast, not an official warning. Environment and Climate Change Canada issues the actual severe thunderstorm and hail warnings, and Alberta Emergency Alert carries the urgent ones. Use those for safety decisions and use this for "should I park in the garage this afternoon".
Park under cover between mid-afternoon and evening on hot, unsettled July days. Keep patio furniture and anything breakable off exposed decks when a watch is posted. Know whether your home insurance covers hail damage to siding and roofing before a storm, not after. And if a warning is issued while you are driving, pulling under an overpass or into a parkade beats trying to outrun the cell.