The most recent edition on this page is dated May 24, 2026. The next edition date is not locked here yet. Use the historical race-morning weather on this page for planning until the next date is published.
Half
Ottawa Half Marathon
Sunday, May 24, 2026Ottawa City Hall, Ontario, Canada
Goal time
1:35:00
Adjusted time (preview)
1:38:15–1:39:30
+3:15 to +4:30 slower
Challenging conditions. Main factor: elevation. Get your personalised finish time and split-by-split pacing plan with Race Pass.
Based on the historical mean for the race window over the last 10 years, ±5 days.
About 282 m of climbing and 288 m of descent. Hilly.
60% within 2%10% over 6%11 climbs
Impacts
Based on the historical mean for the race window over the last 10 years, ±5 days.
Elevation
High impact
>3%
Heat
Low impact
≤1%
Wind
Moderate impact
1–3%
Total Impact
High impact
>3%
Pace Opportunity
Challenging
ChallengingModerateFavorable
Race Pass: personalised finish time, adjusted splits, and your race-day pacing plan.
Historical weather
1 held edition. Race mornings only, not nearby dates. This is not a forecast.
15°C
9 - 20°C range
Mostly cloudy on average
Historical: mostly cloudy
Historical average
1 held edition. Race mornings only, not nearby dates.
2026
Cloud Cover
66%
0 - 100% range
Wind
9km/h
1 - 20 km/h range • prevailing NNW
Humidity
64%
44 - 93% range
WBGT
15.1°C
13.7 - 15.3°C range
Race morning history
Last 10 years, around the 09:00 start hour. Typical late-May air averages 15°C (about 8°C to 22°C in that window). The bands are that history, not a forecast range. Hover or drag to explore.
Race-morning temperature
Most mornings
11-18°C
Almost all
8-21°C
Humidity
64%
Dew
8°C
WBGT
13°C
15°CAverage
09:00-10:35
Almost all (90%)Most mornings (70%)AverageRain
Blue is most mornings. Dashed lines are the rare tails. Pink is the average. The bands are historical race mornings, not a forecast range. Blue columns are rain on the right scale. This assumes a 1:35. You can set your own time in the app.
Typical race-morning wind
Where the wind usually came from on race morning, not where it was going.
NW
Most frequent (20%)
Wind speed
0-6 km/h
6-13 km/h
13-21 km/h
21+ km/h
A start that feels cool is not a promise about the second half.
Related races
Same city, region or country, when we can resolve them. World majors also point to each other.
- Ottawa 10K
- Ottawa International Marathon
- Chilly Half Marathon
- Oakville 21.1 Half Marathon
- Georgina Marathon
- Niagara Falls Marathon
- Sporting Life 10K Toronto
- Sudbury Rocks Marathon
View race map for this area.
Make sense of the conditions
- Dew point, WBGT and running in the heat
Read the heat and humidity before deciding what pace makes sense.
- When drafting helps your running pace
A group can help, but its pace and the conditions still need to suit you.
- Pacing the climbs and descents
Use the course profile to think about effort, not just splits.
Pacing and conditions FAQ
Beyond conditions
Conditions are only part of the race-day loss
Pacing mistakes often add several minutes, sometimes more than conditions alone, especially when the course and conditions are not ideal.
What your plan includes
Everything you need to turn this race preview into a usable race-day plan.
Personalized pacing
Effort and pace guidance tuned to this course profile.
Weather-adjusted splits
Split targets that account for heat, wind, and elevation.
Heat adaptation & drafting
Adjust for your heat tolerance and drafting preferences.
Get your personalised race plan for Ottawa Half Marathon.
Pacing, splits, and race-day strategy personalised to your fitness and this course.
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