Ottawa is 1.1°C (2°F) warmer by day, Mississauga has 8.6°C (15.5°F) warmer nights, Ottawa gets 281 mm (11.1 in) more rain a year.
Mississauga is at its warmest in July and coolest in January, while Ottawa peaks in July and bottoms out in January. Month for month, Mississauga is the warmer of the two in 9 of 12 months.
Ottawa is the wetter of the two, collecting 966 mm (38 in) of rain a year against 685 mm (27 in) in Mississauga. The most comfortable time to visit is June, July and August in Mississauga and June, July and August in Ottawa.
| Mississauga | Metric | Ottawa |
|---|---|---|
| 🌡️ Temperature | ||
| 18°C | 🌡️Average daytime high | 19.1°C |
| -0.5°C | 🌙Average nighttime low | -9.1°C |
| July | 🔥Hottest month | July |
| January | ❄️Coldest month | January |
| 🌧️ Rain | ||
| 685 mm | 🌧️Annual rainfall | 966 mm |
| July | ☔Wettest month | June |
| February | 🏜️Driest month | February |
| 💨 Climate | ||
| 78% | 💧Average humidity | 84% |
| 4.1 m/s | 💨Average wind speed | 0.6 m/s |
Overnight, Mississauga typically falls to around -0.5°C (31.1°F) while Ottawa settles near -9.1°C (15.6°F).
Mississauga is hottest in July and coldest in January, whereas Ottawa peaks in July and is coolest in January.
Mississauga sees the most rain in July and the least in February; Ottawa is wettest in June and driest in February.
Ottawa feels the more humid of the two, averaging 84% relative humidity against 78%.
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 | Mississauga | Ottawa | ||||
|---|---|---|---|---|---|---|
| Min | Avg | Max | Min | Avg | Max | |
| January | -13.9 | -3.7❄️ | 6.5 | -32.5 | -15❄️ | 2.6 |
| February | -13.4 | -3.3 | 6.8 | -29.8 | -13.5 | 2.9 |
| March | -10.3 | 0.8 | 12 | -23.2 | -5.1 | 12.9 |
| April | -3.1 | 6.7 | 16.4 | -7.6 | 7 | 21.6 |
| May | 2.3 | 12.5 | 22.6 | -1.2 | 12.9 | 26.9 |
| June | 7.8 | 17.2 | 26.5 | 5.5 | 17.6 | 29.7 |
| July | 13 | 20.7🔥 | 28.5 | 9.6 | 20.2🔥 | 30.9 |
| August | 13.3 | 20.6 | 28 | 8.2 | 19.4 | 30.6 |
| September | 8.5 | 17.1 | 25.7 | 2.5 | 15.3 | 28 |
| October | 2.5 | 11.4 | 20.3 | -3.9 | 9.4 | 22.6 |
| November | -3.3 | 5.4 | 14 | -11.2 | 1.9 | 14.9 |
| December | -9.2 | -0.3 | 8.6 | -25.8 | -9.9 | 6 |
| Annual Avg | -0.5 | 8.8 | 18 | -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 Mississauga and Ottawa feel alike; where they separate, they are genuinely different places to be.
Hover or tap any point to read the exact figures. Mississauga Ottawa
See how Mississauga 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 Mississauga 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°C (64.4°F) in Mississauga — roughly 1.1°C (2°F) warmer by day. Nights are milder in Mississauga, with average lows of -0.5°C (31.1°F) versus -9.1°C (15.6°F).
Mississauga is hottest in July, averaging highs of about 28.5°C (83.2°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 -13.9°C (7°F) at the low point of the year in Mississauga.
Ottawa is the wetter city, collecting about 966 mm (38 in) of rain a year versus 685 mm (27 in) in Mississauga. Mississauga is wettest in July and driest in February; 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 78% in Mississauga.
The most comfortable months in Mississauga 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.
Mississauga is the warmer city in 9 of the 12 months of the year. The gap is widest in January, about 11.3°C (20.3°F), and narrowest in April, about 0.3°C (0.5°F).
Ottawa has the bigger seasonal swing, about 35.2°C (63.4°F) between its coldest and hottest months versus 24.4°C (43.9°F) in Mississauga — so Mississauga has the steadier, more even climate.
It depends what matters most to you: choose Ottawa for warmer weather, pick Mississauga if you prefer drier conditions and go for Mississauga 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 Mississauga and Ottawa, not a single year's weather or a short-range forecast.
