The 2025 event has concluded.

Marathon Eryri (Snowdonia Marathon)

Llanberis, UK, England · October 25, 2025

46°·47° high·Windy·Light rain

Race Day Weather

46°at start

47° high

Windy

Light rain

Cool and wet, adjust for winds

Runners will face cool temperatures starting at 46°F, remaining steady throughout the race. Wind speeds will peak at 19 mph with gusts up to 37 mph, becoming a headwind from miles 14 to 22. With a light rain expected, hydration will be crucial, especially on the hilly terrain, particularly during climbs at miles 3-5 and 23-24. Runners should adjust their pacing strategy to account for the challenging conditions.

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Pace Calculator

Distance: 26.2mi

Target Finish Time

0:00:00

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Race Info

The inaugural Snowdonia Marathon was held in 1982, and was conceived as a dramatic alternative to the numerous city and town races becoming so popular. The demanding and spectacular route, encircling Snowdon, Wales’ and England’s highest peak, has given the event a unique place in the annual marathon calendar ever since. Source

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FAQ

When is the 2025 Marathon Eryri (Snowdonia Marathon)?

The 2025 Marathon Eryri (Snowdonia Marathon) will be held on Saturday October 25, 2025.

What will the weather be like for the 2025 Marathon Eryri (Snowdonia Marathon)?

The forecast calls for a high of 52°F and a low of 44°F with a 100% chance of rain. Check our detailed hourly forecast above for the best marathon race plan.

Historical Weather

Based on 14 years of data

Avg Temp

52°F

L:51° H:54°

RunScore

Conditions

Rain Freq

93%

13 of 14 yrs

Wind22mph

Dew47°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

Year	Low / High	Rain	Dew Point
2024 Marathon Eryri (Snowdonia Marathon) Becoming cloudy in the afternoon with rain. 2024	51°/55°	Light	48°
2023 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with a chance of rain throughout the day. 2023	53°/54°	Light	48°
2022 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with rain. 2022	59°/63°	Light	57°
2018 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with a chance of rain throughout the day. 2018	42°/43°	Light	31°
2017 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with afternoon rain. 2017	54°/55°	Light	53°
2016 Marathon Eryri (Snowdonia Marathon) Cloudy skies throughout the day with afternoon rain. 2016	53°/54°	Light	52°
2015 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with a chance of rain throughout the day. 2015	48°/50°	Light	44°
2014 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with rain in the morning and afternoon. 2014	53°/55°	Light	48°
2013 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with a chance of rain throughout the day. 2013	54°/56°	Light	49°
2012 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with morning rain. 2012	43°/45°	-	31°
2011 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with rain. 2011	51°/57°	Light	52°
2010 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with a chance of rain throughout the day. 2010	48°/52°	Light	46°
2009 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with rain. 2009	55°/59°	Light	55°
2008 Marathon Eryri (Snowdonia Marathon) Partly cloudy throughout the day with rain. 2008	50°/52°	Light	48°

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