Cybi Coastal Marathon
Cybi Coastal Marathon race day weather
Comfortable temps, moderate wind, chance of rain
Mild 59°F temps at gun time mean comfortable early miles without overheating risk. Moderate winds around 13mph may affect pacing on open sections of the course. There's a chance of rain, so have a backup gear plan ready. High humidity (82%) will make it harder to cool down through sweat — increase fluid intake accordingly.
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Cybi Coastal Marathon route and elevation
The Cybi Coastal Marathon course has about 2,512 ft (766 m) of climbing and 2,495 ft (760 m) of descent, a net rise of about 17 ft (5 m). It is hillier than 81% of the marathon courses racecast.io has mapped, measured by what the hills cost in time. The hardest mile is mile 22, with 589 ft (180 m) of climbing and a 3.1% average grade.
Biggest climbs
- Miles 21.7 to 21.8: climbs about 280 ft (86 m).
- Miles 21.9 to 22.1: climbs about 210 ft (64 m).
- Miles 22.7 to 22.9: climbs about 200 ft (61 m).
What the hills cost
- 3:30 on a flat course is about 3:32 here (2 minutes slower).
- 4:00 on a flat course is about 4:02 here (2 minutes slower).
- 4:30 on a flat course is about 4:33 here (3 minutes slower).
Hills only, priced mile by mile on the course map. The pace calculator above adds the race-day weather.
Even-effort splits for a 3:30, 4:00 or 4:30 finish
| Mile | Climb | Descent | 3:30 | 4:00 | 4:30 |
|---|---|---|---|---|---|
| 1 | 60 ft | 48 ft | 7:58 | 9:06 | 10:14 |
| 2 | 41 ft | 48 ft | 7:50 | 8:58 | 10:05 |
| 3 | 47 ft | 51 ft | 7:51 | 8:58 | 10:06 |
| 4 | 72 ft | 50 ft | 8:03 | 9:12 | 10:21 |
| 5 | 17 ft | 38 ft | 7:48 | 8:55 | 10:01 |
| 6 | 23 ft | 33 ft | 7:50 | 8:57 | 10:04 |
| 7 | 37 ft | 25 ft | 7:58 | 9:07 | 10:16 |
| 8 | 2 ft | 0 ft | 7:54 | 9:00 | 10:08 |
| 9 | 3 ft | 0 ft | 7:53 | 9:02 | 10:09 |
| 10 | 7 ft | 0 ft | 7:56 | 9:03 | 10:12 |
| 11 | 6 ft | 0 ft | 7:55 | 9:03 | 10:11 |
| 12 | 5 ft | 0 ft | 7:55 | 9:03 | 10:10 |
| 13 | 4 ft | 0 ft | 7:54 | 9:02 | 10:10 |
| 14 | 6 ft | 0 ft | 7:55 | 9:03 | 10:11 |
| 15 | 6 ft | 0 ft | 7:55 | 9:03 | 10:10 |
| 16 | 6 ft | 0 ft | 7:56 | 9:03 | 10:11 |
| 17 | 6 ft | 0 ft | 7:55 | 9:03 | 10:11 |
| 18 | 107 ft | 96 ft | 7:57 | 9:06 | 10:14 |
| 19 | 111 ft | 104 ft | 7:56 | 9:03 | 10:12 |
| 20 | 151 ft | 110 ft | 8:12 | 9:23 | 10:33 |
| 21 | 145 ft | 91 ft | 8:19 | 9:31 | 10:42 |
| 22 | 589 ft | 424 ft | 9:18 | 10:37 | 11:57 |
| 23 | 373 ft | 138 ft | 9:58 | 11:23 | 12:48 |
| 24 | 525 ft | 843 ft | 7:02 | 8:02 | 9:03 |
| 25 | 97 ft | 350 ft | 7:07 | 8:09 | 9:10 |
| 26 | 116 ft | 95 ft | 8:02 | 9:11 | 10:19 |
| Last 0.2 | 16 ft | 27 ft | 1:43 | 1:57 | 2:12 |
Explore the Cybi Coastal Marathon course with the weather and your pace along the route, or compare it with other races.
About the Cybi Coastal Marathon
The Cybi Coastal Marathon is a 26.2-mile trail race around Holy Island (Ynys Cybi) on the north Wales coast, starting and finishing at the RNLI station on Newry Beach in Holyhead. The route follows the Anglesey Coastal Path past South Stack lighthouse, Silver Bay, Rhoscolyn, and Trearddur Bay before a climb over Holyhead Mountain (Mynydd Twr). A shorter 25-kilometer option, the Half Cybi, follows the same course until diverging near Penrhos. Entries are capped at roughly 200 runners per distance and open each January 1, benefiting the RNLI Holyhead and Trearddur Bay lifeboat stations.
