Dark Sky Odds

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

March is the best month for stargazing at Rokua National Park: on average 22 clear, moonless hours of full darkness, and 16% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 48% 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 · Finland

MarchBest month
106Clear moonless dark hours a year
48%darker than … of Europe’s land
16%Nights with ≥ 2 such hours (March)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January9%151928%
February7%111408%
March16%229922%
April2%2824%
May0%00—
June0%00—
July0%00—
August0%00—
September8%96813%
October11%1714112%
November8%121797%
December9%172058%

No astronomical darkness (May, June, July, August): 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 than48% of Europe’s land
Light pollutionnoticeable light glow
Sky-glow index (own, VIIRS) — Darkest spot we found3.96
Sky-glow index (own, VIIRS) — at the official map point4.26
Sky-glow index (own, VIIRS) — median across the area5.29
Darkest spot we found64.558, 26.475 (map) — within 2.3 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 202611.28%
9 December 20268–9 December 202612.89%
7 January 20277–8 January 202712.59%
6 February 20276–7 February 202710.77%
8 March 20277–8 March 20277.716%
6 April 20276–7 April 20272.02%
6 May 20276–7 May 20270.00%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.00%
2 August 20271–2 August 20270.00%
31 August 202731 August 2027 – 1 September 20270.00%
30 September 202729–30 September 20277.08%

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%54%8.247°
Geminids *13–14 December 20267%20%13.058°
Geminids *14–15 December 20267%28%11.258°
Quadrantids3–4 January 202722%13%14.872°
Lyrids *22–23 April 202722%96%2.250°
Lyrids *23–24 April 202712%90%1.848°
Eta Aquariids *5–6 May 2027—0%0.0—
Eta Aquariids *6–7 May 2027—0%0.0—
Perseids *12–13 August 2027—84%0.0—
Perseids *13–14 August 2027—90%0.0—
Orionids21–22 October 202720%59%0.741°
Leonids *17–18 November 202712%83%0.047°
Leonids *18–19 November 202710%73%1.747°
Geminids14–15 December 20277%98%0.058°

* 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