Dark Sky Odds

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

March is the best month for stargazing at Hiidenportti 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 73% 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
90Clear moonless dark hours a year
73%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
January6%101935%
February7%101427%
March16%2210122%
April2%21220%
May0%00—
June0%00—
July0%00—
August0%00—
September8%107413%
October11%1614212%
November6%71784%
December8%122056%

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 than73% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found1.03
Sky-glow index (own, VIIRS) — at the official map point2.01
Sky-glow index (own, VIIRS) — median across the area1.77
Darkest spot we found63.858, 29.125 (map) — within 3.8 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 202611.26%
9 December 20268–9 December 202612.78%
7 January 20277–8 January 202712.56%
6 February 20276–7 February 202710.77%
8 March 20277–8 March 20277.816%
6 April 20276–7 April 20272.72%
6 May 20276–7 May 20270.00%
4 June 20274–5 June 20270.00%
4 July 20273–4 July 20270.00%
2 August 20272–3 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 20267%54%8.048°
Geminids *13–14 December 202612%20%12.859°
Geminids *14–15 December 20265%28%11.259°
Quadrantids3–4 January 202718%13%14.772°
Lyrids *22–23 April 202728%96%1.851°
Lyrids *23–24 April 202732%90%2.550°
Eta Aquariids *5–6 May 2027—1%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 202715%59%0.842°
Leonids *17–18 November 20277%83%0.048°
Leonids *18–19 November 20278%73%1.848°
Geminids14–15 December 20275%98%0.059°

* 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