The short answer
Comrades Marathon weather runs from cold to warm in one day. From 2015 to 2024, down-run starts in Pietermaritzburg averaged 7.4 °C (45 °F) at 05:30, and up-run starts in Durban 15.1 °C (59 °F). By afternoon the air reached about 21 to 27 °C (70 to 81 °F), with High heat stress in three of eight races.
Key takeaways
- Down-run starts averaged 7.4 °C (45 °F); up-run starts on the coast averaged 15.1 °C (59 °F).
- 2015, 2016 and 2017 reached High heat stress; every race since rated Fair.
- The August 2022 race brought the highest dew point in our data, 16.0 °C (61 °F).
On this page
- What is Comrades Marathon weather like?
- What was the weather at each Comrades from 2015 to 2024?
- How does direction change the weather you meet?
- How hot does Comrades get at your finish time?
- Was the August 2022 race hotter?
- How should you plan your Comrades race morning?
- How can you check Comrades weather at your own pace?
- Questions runners ask
- Sources and method
Words this guide uses
- Up run and down run
- Comrades alternates direction; the down run goes from Pietermaritzburg to Durban, the up run from Durban to Pietermaritzburg.
- ERA5
- The Copernicus reanalysis of past weather, hourly, on a grid about 31 km (19 miles) apart.
- WBGT
- Wet-bulb globe temperature, a heat-stress number combining air temperature, humidity, sun and wind.
What is Comrades Marathon weather like?
Comrades Marathon weather is two seasons in one day: a cold, dark 05:30 start and a warm afternoon. From 2015 to 2024, the air rose by 6 to 19 °C (11 to 34 °F) between the gun and the warmest stretch. Our marathon weather history hub compares Comrades with Boston, London and Berlin.
The numbers are our own. We took hourly ERA5 weather at the real date, start time and direction, then timed it to a runner along the course: a pace-timed forecast run backwards, giving the weather for each stretch at the time you would have run it.
| The race at a glance | Comrades Marathon, South Africa |
|---|---|
| Date | A Sunday in late May or June (28 August in 2022) |
| Start | 05:30 |
| Direction | Alternates; 2022 and 2023 were both down runs |
| Distance | 90.3 km (56.1 miles) on our down-run model; 85.91 km (53.38 miles) on the 2024 up run |
| Climbing, down run | About 1,710 m (5,610 ft) up and 2,360 m (7,740 ft) down; the up run reverses it |
| Cut-off | 12 hours |
For other ultras, see our ultra running weather guide.
What was the weather at each Comrades from 2015 to 2024?
Three Tough races, then five Fair ones. The table shows each race for an 11-hour finisher.
| Date | Run | Start | Air at the start, °C (°F) | Warmest air, °C (°F) | Highest dew point, °C (°F) | Peak WBGT, °C (°F), level | Rain, mm (in) | Rating |
|---|---|---|---|---|---|---|---|---|
| 31 May 2015 | Up | 05:30 | 17.3 (63) | 25.6 (78) | 15.3 (60) | 27.1 (81), High | none | Tough |
| 29 May 2016 | Down | 05:30 | 7.1 (45) | 26.1 (79) | 15.2 (59) | 22.9 (73), High | none | Tough |
| 4 Jun 2017 | Up | 05:30 | 15.2 (59) | 26.5 (80) | 13.2 (56) | 25.4 (78), High | none | Tough |
| 10 Jun 2018 | Down | 05:30 | 7.8 (46) | 20.9 (70) | 14.9 (59) | 20.3 (69), Moderate | 0.1 (<0.01) | Fair |
| 9 Jun 2019 | Up | 05:30 | 16.3 (61) | 22.7 (73) | 14.5 (58) | 20.2 (68), Moderate | 0.2 (0.01) | Fair |
| 28 Aug 2022 (late season) | Down | 05:30 | 9.7 (49) | 23.0 (73) | 16.0 (61) | 22.2 (72), Moderate | 0.1 (<0.01) | Fair |
| 11 Jun 2023 | Down | 05:30 | 4.9 (41) | 22.1 (72) | 14.4 (58) | 22.2 (72), Moderate | none | Fair |
| 9 Jun 2024 | Up | 05:30 | 11.7 (53) | 20.9 (70) | 9.6 (49) | 20.1 (68), Moderate | none | Fair |
There was no race in 2020 or 2021.
This is reanalysis, not a thermometer at the start line. ERA5 gives hourly values on a grid about 31 km (19 miles) apart, and four grid points cover the course. It matches the race's own records in most years we could check. For 2023, comrades.com gives Pietermaritzburg 5 °C (41 °F) at its coolest; our start reads 4.9 °C (41 °F). For 2017, it gives Durban a low of 11 °C (52 °F), while our start reads 15.2 °C (59 °F): the coastal grid point includes warm sea, which keeps nights milder.
How does direction change the weather you meet?
It changes the start most. Down runs leave inland Pietermaritzburg, about 655 m (2,150 ft) up, where starts averaged 7.4 °C (45 °F). Up runs leave Durban near sea level, where they averaged 15.1 °C (59 °F).
Up runs also finish inland in the afternoon. Their peak WBGT averaged 23.2 °C (74 °F), against 21.9 °C (71 °F) on down runs. On a down run, the big descents come late: in our profile, the course falls from about 690 m (2,260 ft) at km 56 (mile 35) to the coast, past Fields Hill and Cowies Hill. On an up run, those become climbs in the warmest hours.
How hot does Comrades get at your finish time?
Hotter, and sooner, the longer you're out. On the 2015 up run, the hottest in our data, here is the same race at three finish times.
| Finish time | Warmest air, °C (°F) | Hottest feels like, °C (°F) | Peak WBGT, °C (°F) | Heat stress | Rating |
|---|---|---|---|---|---|
| 9:00 | 25.6 (78) | 29.9 (86) | 26.9 (80) | Moderate from km 36, High from km 42 (mile 26) | Tough |
| 11:00 | 25.6 (78) | 31.5 (89) | 27.1 (81) | Moderate from km 30, High from km 33 (mile 21) | Tough |
| 12:00 | 25.6 (78) | 32.4 (90) | 26.8 (80) | Moderate from km 27, High from km 30 (mile 19) | Tough |
The air peaked the same for everyone, but the 12-hour runner met High heat stress 12 km (7.5 miles) earlier and felt it more in the sun.
Was the August 2022 race hotter?
Not in heat stress, but it was the most humid. The race returned on 28 August 2022, about 11 weeks later than usual. Havenga and colleagues (2022), in the South African Journal of Science, found mid-June to mid-July carries the lowest heat-stress risk, and warned that August raised it.
In our data, the 2022 down run peaked at 22.2 °C (72 °F) WBGT, Moderate, and rated Fair. Its dew point reached 16.0 °C (61 °F), the highest of our eight races. Comrades.com describes it as mild and overcast at the start, and partly cloudy into the early afternoon.
How should you plan your Comrades race morning?
Dress for the start, plan for the afternoon.
- Start: a throwaway top or bin bag. Our guide to what to wear for a marathon has the detail.
- Afternoon: a cap, sunscreen and cooling at every table once heat stress reaches Moderate.
- Know the levels: see WBGT for runners.
The American College of Sports Medicine (2007) warns that heat illness can strike even when it's relatively cool. Official race guidance and medical advice override this article, which is not medical advice.
How can you check Comrades weather at your own pace?
Open the Comrades race page, pick a year and set your finish time. It shows the air, feels like, dew point and heat stress at Polly Shortts, Drummond, Fields Hill and 45th Cutting.
Questions runners ask
How cold is the Comrades start at 05:30?
On a down run, cold. Starts in Pietermaritzburg averaged 7.4 °C (45 °F) in our data, and 2023 began at 4.9 °C (41 °F), with a feels like at running pace as low as 2.9 °C (37 °F) for an 11-hour runner. Up runs start on the coast in Durban, where the air averaged 15.1 °C (59 °F). Either way, it's dark and you'll stand still for a while first.
Is the Comrades up run hotter than the down run?
In our data, slightly. Peak WBGT for an 11-hour runner averaged 23.2 °C (74 °F) on the four up runs and 21.9 °C (71 °F) on the four down runs. Up runs start warmer on the coast and end inland in the afternoon. Four races each way is a small sample, though, and the hottest down run, 2016, still rated Tough.
Why was the 2022 Comrades Marathon held in August?
It was the first race after the 2020 and 2021 cancellations, and it ran on 28 August instead of in June. A 2022 study in the South African Journal of Science warned that August raised the risk of strong heat stress. In our data it rated Fair: peak WBGT 22.2 °C (72 °F), Moderate, but the highest dew point of any Comrades, 16.0 °C (61 °F).
Does the Comrades Marathon Association publish race-day weather?
Yes, in outline. The Histories page on comrades.com lists each race's minimum and maximum temperatures for Pietermaritzburg and Durban, with a one-line description, for recent races. Those are town readings. Our numbers instead follow a runner along the whole course at the hour they reach each stretch, which is why the two can differ by a few degrees.
What should you wear for a 05:30 Comrades start?
Layers you can lose. On a down run, plan for 5 to 10 °C (41 to 50 °F) in the dark: an old top, arm warmers or a bin bag you can drop. By midday you'll want a cap, sunscreen and light colours, because the afternoon reached about 21 to 27 °C (70 to 81 °F) in our data. Our marathon kit guide covers both ends.
Your race, at your pace.
Pick Comrades, Berlin, London or Boston, set your finish time, and see the heat stress, feels like and dew point you’d have met at every landmark, on every race day from 2015 to 2024.
Sources and method
- Copernicus Climate Change Service (ECMWF) (2023). ERA5 hourly data on single levels from 1940 to present
- Comrades Marathon Association (2026). Histories (race-day weather, Pietermaritzburg and Durban)
- Comrades Marathon Association (2024). 2024 Comrades Marathon revised cut-offs
- South African Journal of Science (2022). Increased risk of heat stress conditions during the 2022 Comrades Marathon (Havenga, Coetzee, Burger and Piketh)
- American College of Sports Medicine (2007). Position stand: exertional heat illness during training and competition (Armstrong et al.)
Every Comrades Marathon from 2015 to 2024 (none in 2020 or 2021; 2022 on 28 August), at the real date and the 05:30 start, in each year's direction. Weather is hourly ERA5 reanalysis (Copernicus Climate Change Service, ECMWF) at the four 0.25° grid points the course crosses (near Pietermaritzburg, Cato Ridge, Drummond and Durban); each stretch takes its nearest point. The RunFast engine times a runner along our 90.3 km down-run course model at an even effort for a 9:00, 11:00 or 12:00 finish, with pace adjusted for gradient; up runs use the same course reversed, so timings on up runs are approximate (the 2024 up run measured 85.91 km). At each stretch it reads the air, dew point, feels like at running pace, WBGT (Liljegren et al., 2008, with cloud worked back from ERA5 sunshine) and rain when the runner is there. WBGT levels: Low below 18.3 °C (65 °F), Moderate to 22.8 °C (73 °F), High to 27.8 °C (82 °F), Extreme above, judged on unrounded values. Ratings: Fair at Moderate heat stress, Tough at High or Extreme. Averages are means of the four up runs and four down runs at an 11:00 finish. Climbing is measured from the course profile, counting rises of 3 m (10 ft) or more. Fahrenheit values are our conversions. RunFast is independent of the Comrades Marathon Association.
Wes Thomson
Wes Thomson builds RunFast, which times the heat, humidity and dew point to a runner's own pace along the route, and its sister Windline, live wind forecasts for cyclists. Both run on the same forecast engine. He writes these guides with one focus: what the weather will do to your run, kilometre by kilometre, and how to plan around it.