Ottawa is 0.9°C (1.6°F) warmer by day, Ottawa has 1°C (1.8°F) warmer nights, Ottawa gets 442 mm (17.4 in) more rain a year.
Calgary is at its warmest in July and coolest in January, while Ottawa peaks in July and bottoms out in January. Month for month, Ottawa is the warmer of the two in 8 of 12 months.
Ottawa is the wetter of the two, collecting 966 mm (38 in) of rain a year against 524 mm (20.6 in) in Calgary. The most comfortable time to visit is June, July and August in Calgary and June, July and August in Ottawa.
| Calgary | Metric | Ottawa |
|---|---|---|
| 🌡️ Temperature | ||
| 18.2°C | 🌡️Average daytime high | 19.1°C |
| -10.1°C | 🌙Average nighttime low | -9.1°C |
| July | 🔥Hottest month | July |
| January | ❄️Coldest month | January |
| 🌧️ Rain | ||
| 524 mm | 🌧️Annual rainfall | 966 mm |
| June | ☔Wettest month | June |
| January | 🏜️Driest month | February |
| 💨 Climate | ||
| 71% | 💧Average humidity | 84% |
| 1.3 m/s | 💨Average wind speed | 0.6 m/s |
Overnight, Calgary typically falls to around -10.1°C (13.8°F) while Ottawa settles near -9.1°C (15.6°F).
Calgary is hottest in July and coldest in January, whereas Ottawa peaks in July and is coolest in January.
Calgary sees the most rain in June and the least in January; Ottawa is wettest in June and driest in February.
Ottawa feels the more humid of the two, averaging 84% relative humidity against 71%.
For Ottawa, the pick of the year is June, July and August.
Month by month, here is the coldest night, the average day and the hottest afternoon each city can expect. Switch Compare to read rainfall, humidity, wind or solar instead, and Period to move between the long-term 45-year average and any single year — the shading is a quick warm-to-cool guide.
| Month | Calgary | Ottawa | ||||
|---|---|---|---|---|---|---|
| Min | Avg | Max | Min | Avg | Max | |
| January | -25.1 | -10.1❄️ | 4.9 | -32.5 | -15❄️ | 2.6 |
| February | -22.7 | -7.3 | 8.1 | -29.8 | -13.5 | 2.9 |
| March | -17.5 | -2.2 | 13.2 | -23.2 | -5.1 | 12.9 |
| April | -9.4 | 5.1 | 19.5 | -7.6 | 7 | 21.6 |
| May | -4 | 10.4 | 24.9 | -1.2 | 12.9 | 26.9 |
| June | 1.5 | 14.2 | 26.8 | 5.5 | 17.6 | 29.7 |
| July | 4.8 | 17.5🔥 | 30.1 | 9.6 | 20.2🔥 | 30.9 |
| August | 3.4 | 16.7 | 30 | 8.2 | 19.4 | 30.6 |
| September | -2.6 | 12.1 | 26.8 | 2.5 | 15.3 | 28 |
| October | -9 | 5.5 | 20.1 | -3.9 | 9.4 | 22.6 |
| November | -17.2 | -3.7 | 9.8 | -11.2 | 1.9 | 14.9 |
| December | -23.3 | -9.7 | 4 | -25.8 | -9.9 | 6 |
| Annual Avg | -10.1 | 4 | 18.2 | -9.1 | 5 | 19.1 |
Min / mean / max temperature (°C). 🔥 marks each city's hottest month, ❄️ its coldest; shading runs cool blue to warm red.
The same figures plotted out, so the shape of a typical year is easier to see than in a grid. Where the two lines run close together Calgary and Ottawa feel alike; where they separate, they are genuinely different places to be.
Hover or tap any point to read the exact figures. Calgary Ottawa
See how Calgary and Ottawa stack up against other cities. Swipe for more.
Choose which city to keep, then search for any other city in our database — we'll build the comparison for you.
Quick answers to the questions people ask most when comparing Calgary and Ottawa — each drawn straight from the climate figures above.
Ottawa is the warmer of the two. It averages daytime highs of 19.1°C (66.4°F) against 18.2°C (64.8°F) in Calgary — roughly 0.9°C (1.6°F) warmer by day. Nights are milder in Ottawa, with average lows of -9.1°C (15.6°F) versus -10.1°C (13.8°F).
Calgary is hottest in July, averaging highs of about 30.1°C (86.3°F), while Ottawa peaks in July at around 30.9°C (87.6°F). That makes Ottawa the hotter of the two at the height of summer.
Ottawa gets colder. In its coldest month (January) overnight lows average about -32.5°C (-26.5°F), compared with -25.1°C (-13.1°F) at the low point of the year in Calgary.
Ottawa is the wetter city, collecting about 966 mm (38 in) of rain a year versus 524 mm (20.6 in) in Calgary. Calgary is wettest in June and driest in January; Ottawa is wettest in June and driest in February.
Ottawa is the more humid of the two, averaging 84% relative humidity over the year against 71% in Calgary.
The most comfortable months in Calgary are June, July and August, when average temperatures are at their mildest.
Ottawa is at its most pleasant around June, July and August, based on the mildest average temperatures of the year.
Ottawa is the warmer city in 8 of the 12 months of the year. The gap is widest in February, about 6.2°C (11.2°F), and narrowest in December, about 0.2°C (0.4°F).
Ottawa has the bigger seasonal swing, about 35.2°C (63.4°F) between its coldest and hottest months versus 27.6°C (49.7°F) in Calgary — so Calgary has the steadier, more even climate.
It depends what matters most to you: choose Ottawa for warmer weather, pick Calgary if you prefer drier conditions and go for Calgary if you want lower humidity. There is no single "better" climate — it comes down to whether you value warmth, dryness or comfort most.
Every figure on this page is calculated from NASA POWER satellite climate data spanning 1981–2025 (45 years). The averages describe the long-term climate of Calgary and Ottawa, not a single year's weather or a short-range forecast.
