Dark Sky Odds

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

September is the best month for stargazing at Izera Dark Sky Park: on average 31 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 51% 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 · Czechia

SeptemberBest month
200Clear moonless dark hours a year
51%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
January9%161739%
February13%1714612%
March18%2913022%
April18%258928%
May7%83424%
June0%00—
July3%31720%
August16%197825%
September22%3111727%
October15%2615217%
November8%111717%
December8%131867%

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 than51% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found3.46
Sky-glow index (own, VIIRS) — at the official map point3.46
Sky-glow index (own, VIIRS) — median across the area3.72
Darkest spot we found50.842, 15.358 (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 202611.08%
9 December 20268–9 December 202611.88%
7 January 20277–8 January 202711.79%
6 February 20276–7 February 202710.713%
8 March 20277–8 March 20279.018%
6 April 20276–7 April 20276.818%
6 May 20276–7 May 20273.77%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.03%
2 August 20271–2 August 20273.316%
31 August 202731 August 2027 – 1 September 20276.316%
30 September 202729–30 September 20278.522%

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 202612%55%6.861°
Geminids *13–14 December 20268%20%10.772°
Geminids *14–15 December 20268%28%9.572°
Quadrantids3–4 January 20275%13%12.372°
Lyrids22–23 April 202757%95%1.372°
Eta Aquariids *5–6 May 202730%0%6.011°
Eta Aquariids *6–7 May 202738%0%6.011°
Perseids *12–13 August 202733%84%3.267°
Perseids *13–14 August 202733%90%2.267°
Orionids21–22 October 202717%59%3.055°
Leonids *17–18 November 202712%82%1.561°
Leonids *18–19 November 202712%73%2.861°
Geminids14–15 December 20278%98%0.072°

* 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