Climate guideThirty-year normals for Ottawa
Ottawa climate by month
Warm-summer humid continental · DfbBest May–Jun · Sep
Annual mean7°day and night
Seasonal swing31°warmest vs coolest
Precipitation959 mm146 wet days a year
45.41° N, 75.70° WElevation 71 mUTC−4 · Eastern Daylight Time
When to goOttawa · weather score
Best timeMay–Jun · Sep
October: high / low13° / 4°
iSummary
What the weather is like
Ottawa has a warm-summer humid continental climate (Köppen Dfb): warm summers, cold winters and precipitation in every season.
The warmest month is July, when afternoons average 27° and nights 16°. January is the coolest month, with highs of -5° and lows of -14°. The difference between the warmest and the coolest month is about 31°, a large swing typical of continental interiors.
About 959 mm of precipitation falls in an average year. July is the wettest month (89 mm, 16 wet days) and September the driest (94 mm, 9 wet days). Cloud cover ranges from 31% in July to 53% in December.
Year in figures
- Hottest afternoons
- 27° · July
- Coldest nights
- -14° · January
- Wettest month
- July
- Driest month
- September
- Clearest skies
- July · 31% cloud
- Longest day
- 15 h 39 min
- Shortest day
- 8 h 45 min
iiCharts
Twelve months at a glance
Temperature and precipitation
Daily high/low range bars, monthly precipitation columnsTemperature curve
Average high, lowDaylight
Hours between sunrise and sunset on the 15th of each monthiiiData table
Climate normals month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Average high | -5° | -3° | 3° | 11° | 20° | 24° | 27° | 26° | 21° | 13° | 6° | -1° |
| Average low | -14° | -13° | -7° | 1° | 8° | 13° | 16° | 15° | 10° | 4° | -2° | -9° |
| Precipitation | 68 mm | 58 mm | 62 mm | 73 mm | 85 mm | 93 mm | 89 mm | 89 mm | 94 mm | 88 mm | 83 mm | 77 mm |
| Wet days (≥1 mm) | 10.3 | 11 | 11.8 | 12.2 | 10.5 | 13.5 | 15.8 | 13.8 | 8.7 | 11.7 | 12.3 | 14.5 |
| Cloud cover | 49% | 47% | 45% | 45% | 41% | 37% | 31% | 32% | 37% | 43% | 52% | 53% |
| Daylight | 9h 07 | 10h 25 | 11h 52 | 13h 30 | 14h 53 | 15h 39 | 15h 20 | 14h 08 | 12h 34 | 11h 00 | 9h 32 | 8h 45 |
| Month score | 26 | 25 | 24 | 30 | 71 | 65 | 59 | 64 | 77 | 42 | 20 | 15 |
ivMonth by month
Ottawa in every month
January26
-5° / -14°
68 mm · 10.3 wet days
February25
-3° / -13°
58 mm · 11 wet days
March24
3° / -7°
62 mm · 11.8 wet days
April30
11° / 1°
73 mm · 12.2 wet days
May71
20° / 8°
85 mm · 10.5 wet days
June65
24° / 13°
93 mm · 13.5 wet days
July59
27° / 16°
89 mm · 15.8 wet days
August64
26° / 15°
89 mm · 13.8 wet days
September77
21° / 10°
94 mm · 8.7 wet days
October42
13° / 4°
88 mm · 11.7 wet days
November20
6° / -2°
83 mm · 12.3 wet days
December15
-1° / -9°
77 mm · 14.5 wet days