Dark Sky Odds

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

March is the best month for stargazing at Risnjak National Park: on average 39 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 59% 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 · Croatia

MarchBest month
317Clear moonless dark hours a year
59%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%2517314%
February19%2814619%
March25%3913729%
April18%2510224%
May13%157220%
June13%114625%
July18%216333%
August26%369837%
September24%3512628%
October17%2815318%
November13%1916812%
December20%3417320%

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 than59% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found2.36
Sky-glow index (own, VIIRS) — at the official map point4.60
Sky-glow index (own, VIIRS) — median across the area3.30
Darkest spot we found45.492, 14.708 (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 202610.713%
9 December 20268–9 December 202611.720%
7 January 20277–8 January 202711.516%
6 February 20276–7 February 202710.719%
8 March 20277–8 March 20279.225%
6 April 20276–7 April 20277.318%
6 May 20275–6 May 20275.513%
4 June 20274–5 June 20273.513%
4 July 20273–4 July 20273.318%
2 August 20271–2 August 20275.026%
31 August 202731 August 2027 – 1 September 20277.226%
30 September 202729–30 September 20278.824%

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 202617%55%6.366°
Geminids *13–14 December 202640%20%10.278°
Geminids *14–15 December 202633%28%9.078°
Quadrantids3–4 January 202723%13%11.568°
Lyrids22–23 April 202738%95%1.378°
Eta Aquariids *5–6 May 202727%0%7.017°
Eta Aquariids *6–7 May 202732%0%7.017°
Perseids *12–13 August 202757%84%3.067°
Perseids *13–14 August 202748%90%2.067°
Orionids21–22 October 202725%59%3.360°
Leonids *17–18 November 202717%82%1.866°
Leonids *18–19 November 202722%73%3.266°
Geminids14–15 December 202733%98%0.078°

* 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