Dark Sky Odds

Stargazing at Bannau Brycheiniog National Park: when is the sky clear and dark?

March is the best month for stargazing at Bannau Brycheiniog National Park: on average 23 clear, moonless hours of full darkness, and 14% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 75% 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 Reserve · national park · United Kingdom · DarkSky International

MarchBest month
131Clear moonless dark hours a year
75%darker than … of Europe’s land
14%Nights with ≥ 2 such hours (March)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January10%161888%
February10%1414310%
March14%2312918%
April15%188421%
May4%42417%
June0%00—
July1%1810%
August4%5746%
September9%1311611%
October8%131538%
November8%131688%
December8%131877%

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 than75% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found0.90
Sky-glow index (own, VIIRS) — at the official map point2.36
Sky-glow index (own, VIIRS) — median across the area2.31
Darkest spot we found51.975, -3.692 (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 202610.88%
9 December 20268–9 December 202612.08%
7 January 20277–8 January 202711.810%
6 February 20276–7 February 202710.710%
8 March 20277–8 March 20279.014%
6 April 20276–7 April 20276.515%
6 May 20275–6 May 20273.54%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.01%
2 August 20271–2 August 20272.74%
31 August 202731 August 2027 – 1 September 20276.04%
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 202615%55%6.860°
Geminids *13–14 December 202612%20%10.871°
Geminids *14–15 December 202613%29%9.571°
Quadrantids3–4 January 202713%13%12.572°
Lyrids22–23 April 202728%95%1.570°
Eta Aquariids *5–6 May 202727%0%5.810°
Eta Aquariids *6–7 May 202718%1%5.710°
Perseids *12–13 August 20278%84%3.266°
Perseids *13–14 August 20277%90%2.067°
Orionids21–22 October 202713%58%2.854°
Leonids17–18 November 202715%82%1.360°
Geminids14–15 December 202713%98%0.071°

* 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