Dark Sky Odds

Stargazing at Poloniny Dark-Sky Park: when is the sky clear and dark?

September is the best month for stargazing at Poloniny Dark-Sky Park: on average 33 clear, moonless hours of full darkness, and 22% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 88% 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

dark-sky park · Slovakia

SeptemberBest month
242Clear moonless dark hours a year
88%darker than … of Europe’s land
22%Nights with ≥ 2 such hours (September)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January10%1818210%
February11%1714711%
March22%3313225%
April22%279529%
May12%135025%
June0%0412%
July8%93624%
August24%298434%
September22%3311928%
October18%3315521%
November13%2017312%
December6%101885%

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 than88% of Europe’s land
Light pollutionvery dark (darkest 5–20 %)
Sky-glow index (own, VIIRS) — Darkest spot we found0.31
Sky-glow index (own, VIIRS) — at the official map point0.46
Sky-glow index (own, VIIRS) — median across the area0.48
Darkest spot we found49.075, 22.508 (map) — within 12 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 202611.013%
9 December 20268–9 December 202611.86%
7 January 20277–8 January 202711.710%
6 February 20276–7 February 202710.711%
8 March 20277–8 March 20279.222%
6 April 20276–7 April 20277.022%
6 May 20276–7 May 20274.312%
4 June 20274–5 June 20271.20%
4 July 20273–4 July 20270.28%
2 August 20271–2 August 20274.024%
31 August 202731 August 2027 – 1 September 20276.524%
30 September 202729–30 September 20278.822%

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 202618%54%6.763°
Geminids *13–14 December 202610%20%10.374°
Geminids *14–15 December 202613%28%9.274°
Quadrantids3–4 January 20278%13%12.071°
Lyrids22–23 April 202742%95%1.374°
Eta Aquariids *5–6 May 202733%0%6.313°
Eta Aquariids *6–7 May 202725%0%6.313°
Perseids *12–13 August 202753%84%3.267°
Perseids *13–14 August 202752%90%2.067°
Orionids21–22 October 202733%59%3.257°
Leonids *17–18 November 202718%83%1.562°
Leonids *18–19 November 202717%73%3.063°
Geminids14–15 December 202713%98%0.074°

* 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