Dark Sky Odds

Stargazing at Boyne Valley National Park: when is the sky clear and dark?

January is the best month for stargazing at Boyne Valley National Park: 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 17% 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

national park · Ireland

JanuaryBest month
165Clear moonless dark hours a year
17%darker than … of Europe’s land
16%Nights with ≥ 2 such hours (January)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January16%2418613%
February15%1814612%
March16%2412619%
April12%157719%
May2%21114%
June0%00—
July0%00—
August4%5648%
September10%1311112%
October12%1715212%
November18%2317213%
December16%2418912%

No astronomical darkness (June, July): 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 than17% of Europe’s land
Light pollutionstrong light pollution
Sky-glow index (own, VIIRS) — Darkest spot we found15
Sky-glow index (own, VIIRS) — at the official map point19
Sky-glow index (own, VIIRS) — median across the area23
Darkest spot we found53.708, -6.458 (map) — within 2.0 km of the Wikidata point (no OSM boundary)

Next new moons

New moonNightMoonless dark hours that nightTypical share of good nights that month
9 November 20268–9 November 202610.818%
9 December 20268–9 December 202612.016%
7 January 20277–8 January 202712.016%
6 February 20276–7 February 202710.815%
8 March 20277–8 March 20278.816%
6 April 20276–7 April 20276.212%
6 May 20275–6 May 20272.52%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.00%
2 August 20271–2 August 20271.24%
31 August 202731 August 2027 – 1 September 20275.74%
30 September 202729–30 September 20278.310%

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 202632%55%6.858°
Geminids *13–14 December 202622%21%10.869°
Geminids *14–15 December 202620%29%9.769°
Quadrantids3–4 January 202723%13%12.874°
Lyrids22–23 April 202727%95%1.568°
Eta Aquariids *5–6 May 202727%0%5.38°
Eta Aquariids *6–7 May 202725%1%5.27°
Perseids *12–13 August 202715%84%3.266°
Perseids *13–14 August 202717%91%2.066°
Orionids21–22 October 202717%58%2.852°
Leonids17–18 November 202732%82%1.358°
Geminids14–15 December 202720%98%0.069°

* 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