Dark Sky Odds

Stargazing at Bardsey Island: when is the sky clear and dark?

March is the best month for stargazing at Bardsey Island: on average 24 clear, moonless hours of full darkness, and 16% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 97% of Europe’s land (NASA VIIRS 2025).

Data updated: 31 December 2025 · Sources and licences

Calculated 5 November 2026 · cloud cover ERA5 2006–2025 · night lights NASA VIIRS 2025

International Dark Sky Sanctuary · United Kingdom · DarkSky International

MarchBest month
148Clear moonless dark hours a year
97%darker than … of Europe’s land
16%Nights with ≥ 2 such hours (March)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January15%2118811%
February16%1914313%
March16%2412918%
April14%168120%
May2%31816%
June0%00—
July0%056%
August6%77010%
September9%1311411%
October10%1415310%
November10%121697%
December12%1818810%

No astronomical darkness (June): the Sun stays above −18° all night.

Climate, not a forecast: these are shares of past nights (ERA5 reanalysis, 2006–2025), not a prediction for a particular night. Check a forecast before you go.

Light pollution

Darker than97% of Europe’s land
Light pollutionamong the darkest 5 % of Europe
Sky-glow index (own, VIIRS) — Darkest spot we found0.071
Sky-glow index (own, VIIRS) — at the official map point0.071
Sky-glow index (own, VIIRS) — median across the area0.071
Darkest spot we found52.758, -4.792 (map) — within the OSM boundary

Next new moons

New moonNightMoonless dark hours that nightTypical share of good nights that month
9 November 20268–9 November 202611.010%
9 December 20268–9 December 202612.012%
7 January 20277–8 January 202712.015%
6 February 20276–7 February 202710.716%
8 March 20277–8 March 20278.816%
6 April 20276–7 April 20276.514%
6 May 20275–6 May 20273.02%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.00%
2 August 20271–2 August 20272.26%
31 August 202731 August 2027 – 1 September 20275.86%
30 September 202729–30 September 20278.59%

Hours with the Sun below −18° and the Moon below the horizon, on the night of the new moon, at the darkest spot.

Meteor showers

ShowerPeak nightChance of a clear peak nightMoon litMoonless dark hours (Sun < −12°)Radiant max. height
Leonids17–18 November 202622%55%6.759°
Geminids *13–14 December 202625%20%10.770°
Geminids *14–15 December 202622%29%9.570°
Quadrantids3–4 January 202728%13%12.773°
Lyrids22–23 April 202735%95%1.569°
Eta Aquariids *5–6 May 202725%0%5.79°
Eta Aquariids *6–7 May 202722%1%5.38°
Perseids *12–13 August 202715%84%3.266°
Perseids *13–14 August 202713%90%2.067°
Orionids21–22 October 202715%58%2.853°
Leonids17–18 November 202722%82%1.359°
Geminids14–15 December 202722%98%0.070°

* The peak falls in daylight in Europe, so both neighbouring nights are shown.

Clear peak night: at least 2 hours with ≤ 20 % cloud while the Sun is below −12°, on the same calendar night ± 1 in 2006–2025.

How we calculate