Weather in Ottawa - 14-day forecast

Detailed weather forecast for Ottawa, Canada: daytime and night temperature, rain, sunrise and sunset - today and for the next two weeks.

Forecast for the next days in Ottawa

today🌧️ 21°💧 3.2 mm

Sun☀️ 21°💧 0.1 mm

Mon🌤️ 23°💧 0.2 mm

Tue🌧️ 22°💧 0.4 mm

Wed🌧️ 21°💧 5.2 mm

Thu☁️ 12°💧 1.4 mm

Fri☀️ 13°💧 0.1 mm

Sat☀️ 15°💧 0.5 mm

Forecast vs 1991-2020 climate normal

How does the current forecast compare with normal?

We compare the coming days with weather usually observed at this time of year.

NASA POWER

Thursday 10 Sept in Ottawa, the forecast high is 12°C. Typical daytime temperatures at this time of year range from 19°C to 26°C, so it will be exceptionally cool. It is cooler than 99% of similar days.

Saturday 5 Sept

21°Cnear normal

usually 19°C–26°C

night: warmer than usual rain: more rain than usual wind: stronger than usual

Sunday 6 Sept

21°Cnear normal

usually 19°C–26°C

night: warmer than usual rain: typical rainfall wind: stronger than usual

Monday 7 Sept

23°Cnear normal

usually 19°C–26°C

night: exceptionally warm rain: typical rainfall wind: exceptionally strong

Tuesday 8 Sept

22°Cnear normal

usually 19°C–26°C

night: exceptionally warm rain: typical rainfall wind: typical

Wednesday 9 Sept

21°Cnear normal

usually 19°C–26°C

night: exceptionally warm rain: more rain than usual wind: exceptionally strong

Thursday 10 Sept

12°Cexceptionally cool

usually 19°C–26°C

cooler than 99% of similar days

night: near normal rain: typical rainfall wind: exceptionally strong

Friday 11 Sept

13°Cexceptionally cool

usually 19°C–25°C

cooler than 97% of similar days

night: near normal rain: typical rainfall wind: exceptionally strong

How warm was this week in previous years?

Each bar shows the average daily high during the same 7-day period in each year.

swipe to see more years →

cooler yearstypical rangewarmer years2026 forecastcurrent forecast

From 1981 to 2025, the 5-11 Sept period averaged 22°C by day. The coolest year was 1986 (18°C) and the warmest was 2015 (28°C). The current forecast averages 19°C - lower than in 91% of historical years.

Historical reference: NASA POWER daily gridded data (MERRA-2), the 1991-2020 normal and a +/- 7-day calendar window. The typical range is the 20th-80th percentile. This is not a city weather-station reading and does not change the current forecast. NASA POWER Daily API.

14-day forecast - Ottawa

Ottawa - 14-day weather forecast infographic

Ottawa 30 & 45-day weather - long-range outlook

Next 15 days · forecast

20°

around 16° at night · days with rain: 7

Weeks 3-4 · avg for September

22°

around 11° at night · rain chance 0%

Weeks 5-7 · avg for October

14°

around 5° at night · rain chance 0%

The 30 & 45-day outlook for Ottawa: the next 15 days are a numerical forecast updated daily - on average 20° by day and 16° at night. Further out we rely on multi-year climate averages: around 22° in September, and about 14° in October. Forecasts beyond two weeks are indicative only.

Day-by-day forecast for Ottawa

Saturday5 September 2026

🌧️21°light rain

sunrise 06:29 · sunset 19:33 · night 15° · evening 18° · rain 3.15 mm · humidity 73% · wind 4 m/s · clouds 56%

Sunday6 September 2026

☀️21°clear sky

sunrise 06:30 · sunset 19:32 · night 15° · evening 19° · rain 0.12 mm · humidity 51% · wind 3 m/s · clouds 1%

Monday7 September 2026

🌤️23°a few clouds

sunrise 06:31 · sunset 19:30 · night 18° · evening 20° · rain 0.24 mm · humidity 50% · wind 4 m/s · clouds 13%

Tuesday8 September 2026

🌧️22°light rain

sunrise 06:32 · sunset 19:28 · night 17° · evening 19° · rain 0.43 mm · humidity 66% · wind 2 m/s · clouds 98%

Wednesday9 September 2026

🌧️21°light rain

sunrise 06:34 · sunset 19:26 · night 20° · evening 23° · rain 5.22 mm · humidity 95% · wind 8 m/s · clouds 100%

Thursday10 September 2026

☁️12°overcast clouds

sunrise 06:35 · sunset 19:24 · night 11° · evening 11° · rain 1.35 mm · humidity 69% · wind 8 m/s · clouds 96%

Friday11 September 2026

☀️13°clear sky

sunrise 06:36 · sunset 19:22 · night 9° · evening 17° · rain 0.12 mm · humidity 54% · wind 4 m/s · clouds 1%

Saturday12 September 2026

☀️15°clear sky

sunrise 06:37 · sunset 19:20 · night 12° · evening 20° · rain 0.54 mm · humidity 52% · wind 3 m/s · clouds 9%

Sunday13 September 2026

☁️19°overcast clouds

sunrise 06:38 · sunset 19:18 · night 18° · evening 23° · rain 0.45 mm · humidity 65% · wind 6 m/s · clouds 99%

Monday14 September 2026

🌧️22°light rain

sunrise 06:40 · sunset 19:16 · night 22° · evening 30° · rain 1.77 mm · humidity 85% · wind 4 m/s · clouds 44%

Tuesday15 September 2026

🌧️27°moderate rain

sunrise 06:41 · sunset 19:14 · night 24° · evening 31° · rain 6.69 mm · humidity 80% · wind 4 m/s · clouds 66%

Wednesday16 September 2026

🌤️28°scattered clouds

sunrise 06:42 · sunset 19:12 · night 24° · evening 33° · rain 0.72 mm · humidity 68% · wind 3 m/s · clouds 27%

Thursday17 September 2026

🌧️28°light rain

sunrise 06:43 · sunset 19:10 · night 22° · evening 28° · rain 3.18 mm · humidity 66% · wind 7 m/s · clouds 50%

Friday18 September 2026

🌤️14°a few clouds

sunrise 06:45 · sunset 19:09 · night 7° · evening 12° · rain 2.07 mm · humidity 50% · wind 8 m/s · clouds 21%

Saturday19 September 2026

☁️9°overcast clouds

sunrise 06:46 · sunset 19:07 · night 4° · evening 9° · humidity 47% · wind 5 m/s · clouds 100%

UV index in Ottawa - is it safe to sunbathe?

Today the UV index in Ottawa is 4 (moderate) - unprotected fair skin can burn in about 50 minutes. Seek shade around midday. SPF 30+, sunglasses and a hat for longer stays.

Air quality and smog in Ottawa

Air quality in Ottawa is currently very good. Fine particulate PM2.5: 2.6 µg/m³, PM10: 2.6 µg/m³.

City	PM2.5 (µg/m³)	PM10 (µg/m³)	Air quality
Ottawa	2.6	2.6	very good

Based on PM2.5 thresholds. Station readings, updated daily (last reading: 2026-09-04, 21:00).

Ottawa weather through the year

Warmest, driest months on average: April, May, June, July.

Upcoming public holidays in Canada: Labour Day — 7 September · National Day for Truth and Reconciliation — 30 September · Thanksgiving — 12 October.

Nearby and related places

GatineauMontrealMarkhamTorontoQuebec CitySurreyMississauga

FAQ - Ottawa weather

What is the weather like in Ottawa today?

Today it is about 21° during the day and 15° at night, light rain.

How far ahead can I check the forecast for Ottawa?

This page shows a detailed 14-day forecast plus the long-term monthly climate, so you can plan both a short trip and a holiday months ahead.