Dark Sky Odds

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

September is the best month for stargazing at Białowieża National Park: on average 33 clear, moonless hours of full darkness, and 23% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 84% 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 · Poland

SeptemberBest month
205Clear moonless dark hours a year
84%darker than … of Europe’s land
23%Nights with ≥ 2 such hours (September)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January7%131867%
February13%1814512%
March19%3112924%
April21%258031%
May5%61831%
June0%00—
July2%1426%
August20%236934%
September23%3311329%
October18%3315321%
November9%131717%
December6%101886%

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 than84% of Europe’s land
Light pollutionvery dark (darkest 5–20 %)
Sky-glow index (own, VIIRS) — Darkest spot we found0.45
Sky-glow index (own, VIIRS) — at the official map point0.57
Sky-glow index (own, VIIRS) — median across the area0.60
Darkest spot we found52.775, 23.925 (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 202611.09%
9 December 20268–9 December 202612.06%
7 January 20277–8 January 202711.87%
6 February 20276–7 February 202710.713%
8 March 20277–8 March 20279.019%
6 April 20276–7 April 20276.321%
6 May 20276–7 May 20272.85%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.02%
2 August 20271–2 August 20272.220%
31 August 202731 August 2027 – 1 September 20276.020%
30 September 202729–30 September 20278.323%

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 202615%54%7.059°
Geminids *13–14 December 20268%20%10.870°
Geminids *14–15 December 20268%28%9.770°
Quadrantids3–4 January 202715%13%12.574°
Lyrids *22–23 April 202743%95%1.370°
Lyrids *23–24 April 202745%90%2.570°
Eta Aquariids *5–6 May 202743%0%5.58°
Eta Aquariids *6–7 May 202743%0%5.58°
Perseids *12–13 August 202750%84%3.367°
Perseids *13–14 August 202748%90%2.267°
Orionids21–22 October 202717%59%2.753°
Leonids *17–18 November 202715%83%1.359°
Leonids *18–19 November 202713%73%2.859°
Geminids14–15 December 20278%98%0.070°

* 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