Calgary has seen more than 100 mm of rain in July, with more expected

CTV News

4 days ago

As expected, there was a substantial amount of rain in the Calgary area over the weekend, with some communities recording more than 40 mm between Friday to Sunday.
The rainfall total at the official Environment and Climate Change Canada (ECCC) weather station at the YYC Calgary International Airport showed just under 50 mm from Thursday to Saturday.
This precipitation comes on the heels of a wet end to June and a soggy start of July in Calgary – linked mostly to a few noteworthy rain events.
Many of the storms in the Calgary area recently have included variable rainfall amounts (e.g. some communities have recorded higher totals than others), with the overall region trending toward a wetter than average month of July.
According to ECCC, in the first 20-days of July, there has been 101.8 mm of rain recorded at the airport – 36.1 mm more than the average total for the entire month of July.
It's even more significant given that July is typically the second-wettest month in Calgary.
According to the Canadian Climate Normals data from ECCC (1991 to 2020), the wettest months in Calgary are June (average of 112.7 mm of precipitation), July (average of 65.7 mm of precipitation) and August (average of 53.8 mm of precipitation).
Those three months are usually responsible for more than half of the annual precipitation in Calgary, or a combined 232.2 mm out of 445.4 mm annually.
The precipitation total for June and July - up to and including July 20, 2025 - is already 196.2 mm, with most of that falling between June 20 and July 19.
In some ways, this moisture is much needed for the Calgary area, given that both the winter and spring were unusually dry. However, the delivery or amount over duration of this summer's rain might eliminate some of the apparent benefits.
June 2025 brought in 94.4 mm of rain to Calgary – a little shy of the monthly average of 112.7 mm. However, most this precipitation fell over a short period of time, meaning not all of that moisture would have been absorbed by an already saturated surface.
More than two-thirds of June's rain was recorded over the last 10-days of the month, with most of that rain falling over a two-day period.
July has had similar 'all or nothing' events – including this past weekend - and we are potentially heading into another.
More rain is expected in central and southern Alberta this week – starting on Monday and Tuesday.
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Two systems are expected to converge over south-central Alberta over the next 24-hours, making it difficult to pinpoint the locations that will see the highest accumulations, but it seems likely the bulk should land on the western side of the aforementioned area – extending from the U.S. border south of Lethbridge, north to Red Deer and east and west of Highway 2 and the QEII corridors.
On the high end of precipitation estimates, there is the potential for another 30 to 50 mm of rain in Calgary over the next two days. On the low end, there is a chance of 15 to 30 mm of rain by Wednesday.
More persistent rain is expected to start in Calgary by the late afternoon or early evening on Monday and continue through to Tuesday night.
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Colder air will also be drawn into the province from the northern system, limiting Tuesday's daytime high to around 12-degrees below average for Calgary.
In the higher elevations along the foothills, there is a chance of mixed precipitation and/or snow overnight Monday and early Tuesday as lows in that area could potentially sit close to 0 C.