Calgary's weather is quite unusual compared to the weather in the rest of Canada. Where Eastern Canada and B.C. are quite humid, with ample rain and snow, Calgary is very dry most of the time, with an average annual precipitation of 41 cm (16 inches). While many Canadian homes have de-humidifiers, most Calgary homes have humidifiers.

The three months with the most precipitation are June, with an average of 80 mm (3 in), July (68 mm or 2.7 in) and May (60 mm or 2.5 in). The dryness does have one benefit, though: Calgary is quite sunny. The summer months have an average of 9 hours of bright sunshine each day, and average daily maximum temperatures of 22°C (72°F).  In fact, because of Calgary's latitude and extra-long summer days, you can get a surprisingly large number of hours of bright sunshine per day; Calgary's record is 16.2 hours of bright sunshine in a single day (June 23, 1973).

Another unique aspect of Calgary weather is the Chinook ; although other parts of Alberta and Saskatchewan are affected by this warm wind from the west, Calgary and Lethbridge are the cities which experience the strongest Chinooks. In winter, a strong Chinook wind can increase the temperature by 20°C (36°F), so that temperatures can go from -10°C (15°F) to 10 ° C (50°F) in a few hours. Of course, Calgary can have very cold winter weather also, with temperatures dipping as low as -30°C (-22°F) at times; but throughout the winter, the daily high temperature is usually just a degree or two below freezing. Due to the melting caused by Chinooks, winter snow cover is usually quite thin; on average, the snow is only 6 cm (just over 2 in) deep in the snowiest month. 

It is not only in winter that Calgary's temperatures vary a great deal.  Because of its relatively high elevation (1,084 metres or 3,557 feet above sea level) and the influence of the nearby Rocky Mountains, the city experiences temperature swings throughout the year.  Typically  summer evenings cool off, even after a warm day.  The average daily maximum temperature in July is 23° C (76° F), and the average daily minimum temperature in that month is 9° C (48° F).  Yet the temperature on a July day can get up around 30° C (90° F), and the temperature on a July evening can drop as low as the freezing mark. 

Regardless of how fine the weather looks on a summer day, it's always wise to set off from your hotel with a light jacket in case conditons change while you are out.  Having a spare jacket with you becomes all the more important if you go out in the evening, as there is a good chance the air will have cooled off by the time you return to your accommodation later at night.  This is something you need to keep in mind if you attend the evening chuckwagon races during the Calgary Stampede.  (For more information about this annual, ten-day festival of Western, you may want to read Inside Calgary : Stampede : First-time Visitors here at Tripadvisor.)  

Just as is the case with the other seasons, autumn temperatures can be all over the map.  Sometimes Calgary experiences a snowfall fairly early in September, but this can be followed by quite an extended period of pleasant weather that may last into October.  If autumn brings a period of warm, sunny days and cool nights, it is called "Indian Summer."

Halloween, which occurs at the end of October, often marks the onset of colder weather.  Calgary parents know that they have to provide their children with Halloween costumes that are big enough to fit over a snow suit.  If a cold front has arrived in time for Halloween, the trick-or-treaters who come to your door look quite comical -- like the 4-year-old girl who looks like a cross between a Fairy Princess and the Michelin Man. 

Calgary's spring weather is unstable.  Some April and May days are sunny and warm, indeed hot.  Yet April, May and sometimes even June(!) can bring snow.  When it snows in late spring / early summer, the snow typically is wet and heavy, unlike winter snow that more often is light and fluffy.  But May snow does not stick around for long.  Soon enough the sun comes out and melts it away.  The most popular time for Calgary gardeners to plant their annuals is the Victoria Day long weekend, i.e., the weekend preceding May 25th.  There is a widespread perception that that is the stage at which plants are safe from frost.  It is a rather naive belief, however, because there sometimes is one more cold snap in late May / early June.  Then gardeners run around covering their new bedding out plants to protect them from overnight frost!

If you need more detailed information on Calgary's climate, you can find detailed statistics on the Environment Canada Calgary climatology page.

When to Go

The most popular single event that attracts visitors to Calgary is the annual ten-day Western-themed festival known as the Calgary Stampede .  It is held every July.  If you want to find out more about it, you may find it useful to read Inside Calgary : Stampede : First-time Visitors here at TripAdvisor.  WARNING : Accommodation is at a premium during the Calgary Stampede .  If you want to take in the Stampede, it would be wise to book your Calgary hotel by March.    

Leisure travelers rarely visit Calgary in isolation.  More often than not, they combine a stop in Calgary with a trip to the Canadian Rockies (popularly envisaged as Jasper , Yoho , Kootenay , Banff and Waterton Lakes National Parks ).  Therefore trip planning should take mountain conditions into consideration.

The best time to visit the mountains is  June through September .  That is when the mountain lakes are thawed and the brilliant turquoise colour of their water can be enjoyed.  The mountain resort towns of Banff, Lake Louise and Jasper tend to be crowded in July and August .  So, if the traveler has the flexibility to avoid the busiest season, it is better to visit the area in June or September .  But if a family with school-aged children can travel only in the busier months of July and August, it is still worth visiting the area.  When it comes to the Canadian Rockies, "busy" is a relative term.  The Rocky Mountain national parks cover a large area, and it takes only a little effort to step into the forest and away from the crowds.   

May and October are transitional months .  These shoulder months can deliver lovely, warm, sunny weather.  On the other hand they also can produce blizzards.  The mountain lakes tend to thaw towards the end of May.  Yet a few of them, like beautiful Moraine Lake, are not yet looking their turquoise best till after the first week of June.  The beginning of October is the time at which some rides and side roads in the mountains start shutting down for the winter.  Activities and access to scenic landmarks remain fairly good up to and including Canadian Thanksgiving , which is celebrated on the second Monday of October (the same day as the United States celebrates Columbus Day).  But, by the middle of October, many winter closures have taken effect.  So, depending on the kind of experience that the visitor is looking for, May and October can be somewhat risky months.  On the other hand, they are months in which the mountain resort towns are quieter and service is more attentive.  These are months that may appeal to the repeat visitor who already has seen the "must see" landmarks in summer.

In the city of Calgary, May and October can be quite pleasant months.  Calgary's deciduous trees get their new spring leaves some time between the first week of April and the first week of May.  Therefore by May the city is looking quite green.  Calgary's yellow and golden fall colours usually are at their peak around mid-late September.  Some fall colour typically lingers into early October.  The month of October can be quite cold, even snowy.  Yet it sometimes produces nice "Indian Summer" weather. 

November is an extremely quiet month in the mountains.  Summer sight seeing and hiking are over, but downhill skiing has not yet begun.

Downhill skiers visit the mountains from December through April and even into early May. 

Winter, say November through March , is not an especially inspiring time to visit Calgary.  Although Calgary does have some of the amenities you would expect a city of one million people to have (a zoo, a city museum, a symphony orchestra, etc.), it does not have the range and depth of museums, art galleries, theatres, shops, etc., that could engage a winter visitor for days on end, in the way that New York City could do.  Winter days are short, and the sidewalk cafes and hanging flower baskets of summer are long gone.  Over the Christmas - New Year period, homes festooned with colourful Christmas lights provide some compensation for the long nights.  But that is not enough to redeem Calgary from a tourist's point of view. 

Posters on the travel discussion boards sometimes ask about visiting Calgary over the Christmas - New Year period.  A visit to Calgary at that time of year is not recommended.  It is a quiet time in the city.  Calgarians use the Christmas - New Year holidays to spend time with their families.  Alternatively they go skiing in the mountains, or else they nip off to a tropical destination for a dose of sun and warmth.

If folks want to visit this region over Christmas and New Year, or at any time during the winter for that matter, they are better off heading to the pretty mountain resort towns of Banff  and Jasper , which are nestled in gorgeous mountain scenery.  This is true even for visitors who are not downhill skiers. 

Calgarians are notorious for enjoying the outdoors. Calgary boasts an enormous park system. In the south is the widespread Fish Creek Provincial Park . In the far north part of the city, there is a 1127 hectare (2,785 acre) park called Nose Hill . It boasts one of the few remaining areas in Alberta where fescue grass grows freely. Prince's Island Park is an oasis in the downtown core. Many other parks are scattered through Calgary such as Edworthy Park , Bowness Park , North and South Glenmore parks and many others offering differing vistas. Some vistas of the mountains and some of the prairies.