Dark Sky Odds

Stargazing at Slovak Karst National Park: when is the sky clear and dark?

March is the best month for stargazing at Slovak Karst National Park: on average 40 clear, moonless hours of full darkness, and 25% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 73% 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 · Slovakia

MarchBest month
299Clear moonless dark hours a year
73%darker than … of Europe’s land
25%Nights with ≥ 2 such hours (March)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January16%2817915%
February18%2614818%
March25%4013430%
April22%279528%
May15%155427%
June2%31027%
July11%124128%
August22%298634%
September27%3812032%
October22%3815525%
November14%2217413%
December12%2118911%

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 than73% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found1.03
Sky-glow index (own, VIIRS) — at the official map point1.33
Sky-glow index (own, VIIRS) — median across the area1.61
Darkest spot we found48.658, 20.392 (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 202610.814%
9 December 20268–9 December 202611.812%
7 January 20277–8 January 202711.716%
6 February 20276–7 February 202710.718%
8 March 20277–8 March 20279.225%
6 April 20276–7 April 20277.222%
6 May 20276–7 May 20274.715%
4 June 20274–5 June 20271.72%
4 July 20273–4 July 20271.211%
2 August 20271–2 August 20274.022%
31 August 202731 August 2027 – 1 September 20276.722%
30 September 202729–30 September 20278.827%

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 202620%54%6.563°
Geminids *13–14 December 202615%20%10.374°
Geminids *14–15 December 202613%28%9.274°
Quadrantids3–4 January 202727%13%11.871°
Lyrids22–23 April 202753%95%1.374°
Eta Aquariids *5–6 May 202727%0%6.313°
Eta Aquariids *6–7 May 202727%0%6.314°
Perseids *12–13 August 202758%84%3.267°
Perseids *13–14 August 202753%90%2.269°
Orionids21–22 October 202735%59%3.257°
Leonids *17–18 November 202720%82%1.763°
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