Dark Sky Odds

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

October is the best month for stargazing at Ceahlău National Park: on average 48 clear, moonless hours of full darkness, and 29% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 69% 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 · Romania

OctoberBest month
340Clear moonless dark hours a year
69%darker than … of Europe’s land
29%Nights with ≥ 2 such hours (October)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January19%3318618%
February16%2314316%
March22%3313624%
April23%2910029%
May13%156523%
June8%83521%
July18%205536%
August27%359338%
September23%3312427%
October29%4815531%
November24%3516821%
December20%2918416%

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 than69% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found1.34
Sky-glow index (own, VIIRS) — at the official map point1.55
Sky-glow index (own, VIIRS) — median across the area1.76
Darkest spot we found46.942, 25.892 (map) — within 5.0 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 202610.824%
9 December 20268–9 December 202611.720%
7 January 20277–8 January 202711.719%
6 February 20276–7 February 202710.716%
8 March 20277–8 March 20279.222%
6 April 20276–7 April 20277.223%
6 May 20276–7 May 20275.013%
4 June 20274–5 June 20272.78%
4 July 20273–4 July 20272.518%
2 August 20271–2 August 20274.727%
31 August 202731 August 2027 – 1 September 20277.027%
30 September 202729–30 September 20278.823%

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 202637%54%6.564°
Geminids *13–14 December 202627%20%10.376°
Geminids *14–15 December 202630%28%9.276°
Quadrantids3–4 January 202732%13%11.770°
Lyrids22–23 April 202755%96%1.377°
Eta Aquariids *5–6 May 202737%0%6.815°
Eta Aquariids *6–7 May 202735%0%6.716°
Perseids *12–13 August 202760%84%3.267°
Perseids *13–14 August 202760%90%2.268°
Orionids21–22 October 202757%59%3.259°
Leonids *17–18 November 202737%83%1.764°
Leonids *18–19 November 202730%73%3.065°
Geminids14–15 December 202730%98%0.076°

* 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