The most recent edition on this page is dated Jun 13, 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.
160.9 km
South Downs Way 100
2027 date not locked yetMatterley Bowl, Hampshire, UK
Goal time
22:00:00
Adjusted time (preview)
About 3615 m of climbing and 3708 m of descent. Hilly. Net downhill.
32% within 2%30% over 6%74 climbs18 climbs over 6%
Impacts
Based on the historical mean for the race window over the last 10 years, ±5 days.
Elevation
Heat
Wind
Total Impact
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.
16°C
12 - 23°C range
Mostly cloudy on average
Historical: mostly cloudy, with moderate winds
Historical average
1 held edition. Race mornings only, not nearby dates.
2026
Cloud Cover
62%
9 - 100% range
Wind
13km/h
6 - 21 km/h range • prevailing WSW
Humidity
73%
50 - 91% range
WBGT
15.4°C
11.0 - 17.5°C range
Race morning history
Last 10 years, around the 05:30 start hour. Typical mid-June air averages 16°C (about 6°C to 23°C in that window). The bands are that history, not a forecast range. Hover or drag to explore.
Race-morning temperature
Most mornings
14-20°C
Almost all
12-22°C
Humidity
69%
Dew
12°C
WBGT
16°C
Rain
0.0 mm/h
18°CAverage
05:30-19:08
Almost all (90%)Most mornings (70%)AverageRain
Year pills: green is favorable heat. Amber is moderate. Red is challenging.
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 13:38. 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.
W
Most frequent (15%)
Wind speed
0-6 km/h
6-13 km/h
13-21 km/h
21+ km/h
Year pills: green is favorable wind. Amber is moderate. Red is challenging. Colours assume no drafting.
A start that feels cool is not a promise about the second half.
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 South Downs Way 100.
Pacing, splits, and race-day strategy personalised to your fitness and this course.
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