Stargazing at Isojärvi National Park: when is the sky clear and dark?
March is the best month for stargazing at Isojärvi National Park: on average 28 clear, moonless hours of full darkness, and 19% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 78% of Europe’s land (NASA VIIRS 2025).
national park · Finland
Month by month
| Month | Nights with ≥ 2 such hours | Clear moonless dark hours | Moonless dark hours | Of them clear |
|---|---|---|---|---|
| January | 8% | 13 | 189 | 7% |
| February | 9% | 12 | 143 | 9% |
| March | 19% | 28 | 109 | 26% |
| April | 5% | 5 | 24 | 21% |
| May | 0% | 0 | 0 | — |
| June | 0% | 0 | 0 | — |
| July | 0% | 0 | 0 | — |
| August | 1% | 1 | 6 | 15% |
| September | 12% | 15 | 87 | 17% |
| October | 13% | 21 | 146 | 14% |
| November | 5% | 8 | 175 | 4% |
| December | 8% | 16 | 202 | 8% |
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 than | 78% of Europe’s land |
|---|---|
| Light pollution | dark rural sky (darkest 20–50 %) |
| Sky-glow index (own, VIIRS) — Darkest spot we found | 0.74 |
| Sky-glow index (own, VIIRS) — at the official map point | 0.82 |
| Sky-glow index (own, VIIRS) — median across the area | 0.85 |
| Darkest spot we found | 61.675, 25.008 (map) — within 2.7 km of the Wikidata point (no OSM boundary) |
Next new moons
| New moon | Night | Moonless dark hours that night | Typical share of good nights that month |
|---|---|---|---|
| 9 November 2026 | 8–9 November 2026 | 11.0 | 5% |
| 9 December 2026 | 8–9 December 2026 | 12.5 | 8% |
| 7 January 2027 | 7–8 January 2027 | 12.3 | 8% |
| 6 February 2027 | 6–7 February 2027 | 10.7 | 9% |
| 8 March 2027 | 7–8 March 2027 | 8.2 | 19% |
| 6 April 2027 | 6–7 April 2027 | 3.8 | 5% |
| 6 May 2027 | 6–7 May 2027 | 0.0 | 0% |
| 4 June 2027 | 4–5 June 2027 | 0.0 | 0% |
| 4 July 2027 | 3–4 July 2027 | 0.0 | 0% |
| 2 August 2027 | 1–2 August 2027 | 0.0 | 1% |
| 31 August 2027 | 31 August 2027 – 1 September 2027 | 2.8 | 1% |
| 30 September 2027 | 29–30 September 2027 | 7.5 | 12% |
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
| Shower | Peak night | Chance of a clear peak night | Moon lit | Moonless dark hours (Sun < −12°) | Radiant max. height |
|---|---|---|---|---|---|
| Leonids | 17–18 November 2026 | 7% | 54% | 7.7 | 50° |
| Geminids * | 13–14 December 2026 | 12% | 20% | 12.2 | 61° |
| Geminids * | 14–15 December 2026 | 10% | 28% | 10.7 | 61° |
| Quadrantids | 3–4 January 2027 | 17% | 13% | 14.3 | 74° |
| Lyrids * | 22–23 April 2027 | 28% | 96% | 1.7 | 56° |
| Lyrids * | 23–24 April 2027 | 28% | 90% | 3.5 | 56° |
| Eta Aquariids * | 5–6 May 2027 | — | 0% | 0.0 | — |
| Eta Aquariids * | 6–7 May 2027 | — | 0% | 0.0 | — |
| Perseids * | 12–13 August 2027 | 25% | 84% | 2.7 | 58° |
| Perseids * | 13–14 August 2027 | 25% | 90% | 2.2 | 58° |
| Orionids | 21–22 October 2027 | 17% | 59% | 1.5 | 44° |
| Leonids * | 17–18 November 2027 | 7% | 83% | 0.2 | 50° |
| Leonids * | 18–19 November 2027 | 3% | 73% | 2.0 | 50° |
| Geminids | 14–15 December 2027 | 10% | 98% | 0.0 | 61° |
* 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.