How dark is the sky at Exmoor National Park?

Modelled zenith brightness from the 2024 World Atlas of Artificial Night Sky Brightness puts Exmoor National Park at about 21.71 mag/arcsec², roughly Bortle class 3. That is an approximation derived from satellite data, not a field measurement; it is certified by DarkSky International as an International Dark Sky Reserve.

How far is Exmoor National Park from Cardiff?

About 51 km in a straight line, heading south-west from Cardiff. Using a 1.3 road-detour factor and staged average speeds that is roughly 66.3 km and 1.1 h of driving — an estimate, not a routed drive time.

When is the next moon-free dark window at Exmoor National Park?

The next stretch of essentially moon-free dark hours runs Nov 3–15 (13 nights), computed from Moon phase and altitude with Skyfield and JPL DE440s. Cloud cannot be known that far ahead; the live seven-night forecast on this page shows real cloud cover once a window is close.

What is the clearest month at Exmoor National Park?

Over 2021–2025, April (43%), May (37%), July (37%) had the highest share of nights with astronomical darkness that stayed clear (weighted cloud cover ≤ 20%); across the year it was 24%. ERA5 reanalysis via Open-Meteo — historical frequency, not a forecast.

United Kingdom · International Dark Sky Reserve

Stargazing at Exmoor National Park

How dark this certified sky really is, how far it is from the nearest cities, a live seven-night forecast for the site itself, and the moon-free nights worth planning around. Official DarkSky International page ↗

Sky at the siteBortle ≈ 321.71 mag/arcsec² · 2024 atlas

From Cardiff~1.1 h51 km straight-line · head south-west · estimated

Next moon-free windowNov 3–1513 nights · moon geometry only

How dark the sky really is at Exmoor National Park

Modelled zenith brightness at the site's coordinates is 21.71 mag/arcsec², which maps to roughly Bortle 3 (what each level means). This is an approximation from the 2024 light-pollution atlas, not a field measurement — and it describes the single point DarkSky lists, not the darkest corner of the reserve.

A genuinely dark rural sky: the Milky Way shows real structure overhead, galaxies and nebulae are rewarding in binoculars and small telescopes, and only a faint glow near the horizon betrays the nearest towns. For most visitors this is the darkest sky they will ever observe under.

Getting to Exmoor National Park

The nearest cities we publish guides for, with the direction to head and a rough drive estimate.

From Cardiff
head south-west · 51 km straight-line · ≈66.3 km by road · ≈1.1 h · evening trip
From Bristol
head south-west · 82 km straight-line · ≈106.6 km by road · ≈1.6 h · evening trip
From Birmingham
head south-west · 192.6 km straight-line · ≈250.4 km by road · ≈3.1 h · weekend trip

Estimated from straight-line distance x a 1.3 road-detour factor and staged average speeds (40 km/h leaving town, 70 km/h regional, 95 km/h highway). It is a rough guide, not a routed drive time.

The next seven nights at Exmoor National Park

Loading the live forecast…

Plan the next 90 days at Exmoor National Park

Moon-free dark windows are astronomy — computable years ahead. Cloud is not: beyond the 16-night forecast nobody knows the weather, and we won't pretend to. What five years of reanalysis can say is how often each month's nights actually stayed clear here.

Nov 3–1513 moon-free nights11% of November nights here stayed clear (2021–2025)
Dec 2–1514 moon-free nights8% of December nights here stayed clear (2021–2025)
Dec 31 – Jan 1314 moon-free nights8% of December nights here stayed clear (2021–2025)

Clear nights by month, 2021–2025

Jan12%
Feb13%
Mar25%
Apr43%
May37%
Jun33%
Jul37%
Aug33%
Sep29%
Oct10%
Nov11%
Dec8%

Clearest months historically: April (43%), May (37%), July (37%); across the year 24% of nights with astronomical darkness stayed clear.

"Clear" = weighted cloud cover (low 0.5 / mid 0.3 / high 0.2) ≤ 20% across the night's astronomical darkness. ERA5 reanalysis via Open-Meteo Archive, 2021–2025 (CC BY 4.0) — historical frequency, not a forecast. Once a window comes within 16 nights, the live forecast above takes over.

Put Exmoor National Park's dark-sky nights on your calendar

Every month has a stretch of nights when the Moon leaves the dark hours at Exmoor National Park essentially moon-free. Subscribe once and each window lands in your own calendar, about a year ahead — no account, no email.

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moon & darkness geometry only — cloud can't be known this far out; check the live forecast above when a window gets close

Questions people ask about Exmoor National Park

How dark is the sky at Exmoor National Park?: Modelled zenith brightness from the 2024 World Atlas of Artificial Night Sky Brightness puts Exmoor National Park at about 21.71 mag/arcsec², roughly Bortle class 3. That is an approximation derived from satellite data, not a field measurement; it is certified by DarkSky International as an International Dark Sky Reserve.
How far is Exmoor National Park from Cardiff?: About 51 km in a straight line, heading south-west from Cardiff. Using a 1.3 road-detour factor and staged average speeds that is roughly 66.3 km and 1.1 h of driving — an estimate, not a routed drive time.
When is the next moon-free dark window at Exmoor National Park?: The next stretch of essentially moon-free dark hours runs Nov 3–15 (13 nights), computed from Moon phase and altitude with Skyfield and JPL DE440s. Cloud cannot be known that far ahead; the live seven-night forecast on this page shows real cloud cover once a window is close.
What is the clearest month at Exmoor National Park?: Over 2021–2025, April (43%), May (37%), July (37%) had the highest share of nights with astronomical darkness that stayed clear (weighted cloud cover ≤ 20%); across the year it was 24%. ERA5 reanalysis via Open-Meteo — historical frequency, not a forecast.

Place name and coordinates: DarkSky International (reviewed 2026-07-15, data 2026-10-13). Light pollution: David Lorenz, World Atlas 2024 (EOG VIIRS, CC BY 4.0), approximate. Cloud: Open-Meteo.com (CC BY 4.0). Moon and darkness geometry: Skyfield + JPL DE440s, computed locally. Drive times are estimates, not routes.