Hamilton is 2.7°C (4.9°F) warmer by day, Hamilton has 4.3°C (7.7°F) warmer nights, Ottawa gets 248 mm (9.8 in) more rain a year.
Hamilton is at its warmest in July and coolest in January, while Ottawa peaks in July and bottoms out in January. Month for month, Hamilton is the warmer of the two in 12 of 12 months.
Ottawa is the wetter of the two, collecting 966 mm (38 in) of rain a year against 718 mm (28.3 in) in Hamilton. The most comfortable time to visit is June, July and August in Hamilton and June, July and August in Ottawa.
| Hamilton | Metric | Ottawa |
|---|---|---|
| 🌡️ Temperature | ||
| 21.8°C | 🌡️Average daytime high | 19.1°C |
| -4.8°C | 🌙Average nighttime low | -9.1°C |
| July | 🔥Hottest month | July |
| January | ❄️Coldest month | January |
| 🌧️ Rain | ||
| 718 mm | 🌧️Annual rainfall | 966 mm |
| July | ☔Wettest month | June |
| February | 🏜️Driest month | February |
| 💨 Climate | ||
| 77% | 💧Average humidity | 84% |
| 3.3 m/s | 💨Average wind speed | 0.6 m/s |
Overnight, Hamilton typically falls to around -4.8°C (23.4°F) while Ottawa settles near -9.1°C (15.6°F).
Hamilton is hottest in July and coldest in January, whereas Ottawa peaks in July and is coolest in January.
Hamilton 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 77%.
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 | Hamilton | Ottawa | ||||
|---|---|---|---|---|---|---|
| Min | Avg | Max | Min | Avg | Max | |
| January | -20.5 | -7.1❄️ | 6.2 | -32.5 | -15❄️ | 2.6 |
| February | -19.6 | -5.9 | 7.8 | -29.8 | -13.5 | 2.9 |
| March | -15.2 | 0.8 | 16.9 | -23.2 | -5.1 | 12.9 |
| April | -6 | 8.3 | 22.7 | -7.6 | 7 | 21.6 |
| May | -0.3 | 13.9 | 28.1 | -1.2 | 12.9 | 26.9 |
| June | 5.5 | 18.7 | 31.9 | 5.5 | 17.6 | 29.7 |
| July | 10.2 | 22🔥 | 33.8 | 9.6 | 20.2🔥 | 30.9 |
| August | 9.6 | 21.4 | 33.2 | 8.2 | 19.4 | 30.6 |
| September | 4.1 | 17.5 | 30.9 | 2.5 | 15.3 | 28 |
| October | -2.4 | 11.3 | 24.9 | -3.9 | 9.4 | 22.6 |
| November | -7.7 | 4.6 | 16.9 | -11.2 | 1.9 | 14.9 |
| December | -14.7 | -3 | 8.8 | -25.8 | -9.9 | 6 |
| Annual Avg | -4.7 | 8.5 | 21.8 | -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 Hamilton and Ottawa feel alike; where they separate, they are genuinely different places to be.
Hover or tap any point to read the exact figures. Hamilton Ottawa
See how Hamilton 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 Hamilton and Ottawa — each drawn straight from the climate figures above.
Hamilton is the warmer of the two. It averages daytime highs of 21.8°C (71.2°F) against 19.1°C (66.4°F) in Ottawa — roughly 2.7°C (4.9°F) warmer by day. Nights are milder in Hamilton, with average lows of -4.8°C (23.4°F) versus -9.1°C (15.6°F).
Hamilton is hottest in July, averaging highs of about 33.8°C (92.8°F), while Ottawa peaks in July at around 30.9°C (87.6°F). That makes Hamilton 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 -20.5°C (-4.9°F) at the low point of the year in Hamilton.
Ottawa is the wetter city, collecting about 966 mm (38 in) of rain a year versus 718 mm (28.3 in) in Hamilton. Hamilton 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 77% in Hamilton.
The most comfortable months in Hamilton 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.
Hamilton is the warmer city in all 12 months of the year. The gap is widest in January, about 7.9°C (14.2°F), and narrowest in May, about 1°C (1.8°F).
Ottawa has the bigger seasonal swing, about 35.2°C (63.4°F) between its coldest and hottest months versus 29.1°C (52.4°F) in Hamilton — so Hamilton has the steadier, more even climate.
On climate alone, Hamilton comes out ahead — it offers warmer days, less rain and lower humidity than Ottawa. Ottawa is the better fit only if you'd actually prefer cooler weather, more rainfall and a more humid climate.
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 Hamilton and Ottawa, not a single year's weather or a short-range forecast.
