Ottawa in August
In August, Ottawa averages 25°C (77°F) during the day and 16°C (62°F) at night, with frequent rain — about 18 days of the month see precipitation (108 mm total).
High seasonConditions are comfortable for sightseeing without being sweltering. Expect daily rain or showers, often in heavy bursts.
August offers comfortable temperatures in Ottawa, with some rain to plan around.
How August compares to the rest of the year in Ottawa
August is one of the warmest months in Ottawa (2nd of 12) and moderately rainy compared to the rest of the year (5th of 12). Daytime temperature runs 13°C above the annual average (12°C). August runs 1°C cooler than July (26°C) and cools 4°C in September (21°C).
August sunrise & sunset in Ottawa
Times shown for Ottawa local time (America/Toronto), calculated for the 15th of August. They shift by a few minutes day to day across the month.
Photography light in Ottawa — August
Golden-hour and blue-hour windows for the 15th of August, in Ottawa's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Ottawa in August
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on August's tier (High season) and Ottawa's popularity.
Crowds & pricing — August in Ottawa
This is a busy month in Ottawa — not the absolute peak, but tourist numbers are clearly elevated. You'll feel it at headline attractions on weekends and in the historic centre, though side streets and lesser-known sights stay manageable. Prices are above off-season but not at their summit. A good week for first-time visitors who want everything open without the worst of the crush.
Why this tier: comfortable tourism weather Northern Hemisphere summer holidays
Sun & mosquito risk — August in Ottawa
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Ottawa in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | -4°C / 24°F | -14°C / 7°F | 73 mm | 18 | — |
| February | -3°C / 26°F | -13°C / 9°F | 77 mm | 17 | — |
| March | 2°C / 36°F | -7°C / 19°F | 78 mm | 18 | — |
| April | 11°C / 51°F | 0°C / 32°F | 117 mm | 17 | — |
| May | 19°C / 67°F | 8°C / 46°F | 73 mm | 16 | — |
| June | 24°C / 74°F | 13°C / 56°F | 119 mm | 18 | — |
| July | 26°C / 79°F | 17°C / 62°F | 100 mm | 18 | — |
| August | 25°C / 77°F | 16°C / 62°F | 108 mm | 18 | — |
| September | 21°C / 70°F | 13°C / 55°F | 78 mm | 15 | — |
| October | 14°C / 57°F | 6°C / 44°F | 115 mm | 18 | — |
| November | 5°C / 42°F | -1°C / 30°F | 74 mm | 17 | — |
| December | 0°C / 32°F | -7°C / 20°F | 83 mm | 17 | — |
Other cities with similar August weather
🌍 See the full ranked list of climate twins for Ottawa in August →
Frequently asked questions
How hot is Ottawa in August?
In August, Ottawa averages a high of 25°C (77°F) and a low of 16°C (62°F) — generally warm.
Does it rain a lot in Ottawa in August?
August is quite rainy in Ottawa, with about 18 rainy days on average.
Is August a good time to visit Ottawa?
August is warm but on the rainy side. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Ottawa in August?
Pack light layers for warm days and cooler evenings, plus a compact umbrella or rain jacket. See the full August packing list for Ottawa for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.