Dark Sky Odds

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

March is the best month for stargazing at Bothnian Sea National Park: on average 29 clear, moonless hours of full darkness, and 20% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 76% 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
136Clear moonless dark hours a year
76%darker than … of Europe’s land
20%Nights with ≥ 2 such hours (March)

Month by month

MonthNights with ≥ 2 such hoursClear moonless dark hoursMoonless dark hoursOf them clear
January9%131867%
February12%1514410%
March20%2911226%
April7%72924%
May0%00—
June0%00—
July0%00—
August2%11113%
September15%189020%
October14%2114615%
November10%141778%
December12%171899%

No astronomical darkness (May, June, July): 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 than76% of Europe’s land
Light pollutiondark rural sky (darkest 20–50 %)
Sky-glow index (own, VIIRS) — Darkest spot we found0.83
Sky-glow index (own, VIIRS) — at the official map point0.73
Sky-glow index (own, VIIRS) — median across the area1.44
Darkest spot we found60.858, 21.125 (map) — within 15 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 202611.210%
9 December 20268–9 December 202612.512%
7 January 20277–8 January 202712.39%
6 February 20276–7 February 202710.812%
8 March 20277–8 March 20278.220%
6 April 20276–7 April 20274.37%
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 20270.02%
31 August 202731 August 2027 – 1 September 20273.32%
30 September 202729–30 September 20277.515%

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 202623%54%7.751°
Geminids *13–14 December 202615%20%12.262°
Geminids *14–15 December 202617%28%10.762°
Quadrantids3–4 January 202717%13%14.274°
Lyrids *22–23 April 202727%95%1.757°
Lyrids *23–24 April 202728%90%3.258°
Eta Aquariids *5–6 May 202733%0%1.8-7°
Eta Aquariids *6–7 May 202725%0%1.5-8°
Perseids *12–13 August 202725%84%3.259°
Perseids *13–14 August 202720%90%2.361°
Orionids21–22 October 202730%59%1.745°
Leonids *17–18 November 202723%82%0.351°
Leonids *18–19 November 202720%73%2.051°
Geminids14–15 December 202717%98%0.062°

* 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