Stargazing at Cíes Islands: when is the sky clear and dark?
August is the best month for stargazing at Cíes Islands: on average 54 clear, moonless hours of full darkness, and 37% of nights have at least two of them (ERA5, 2006–2025). The darkest spot we found there is darker than 21% of Europe’s land (NASA VIIRS 2025).
national park · Spain
Month by month
| Month | Nights with ≥ 2 such hours | Clear moonless dark hours | Moonless dark hours | Of them clear |
|---|---|---|---|---|
| January | 24% | 41 | 175 | 23% |
| February | 26% | 42 | 149 | 28% |
| March | 24% | 42 | 137 | 31% |
| April | 22% | 33 | 108 | 31% |
| May | 27% | 33 | 86 | 38% |
| June | 22% | 23 | 61 | 38% |
| July | 33% | 41 | 78 | 53% |
| August | 37% | 54 | 106 | 50% |
| September | 33% | 50 | 126 | 40% |
| October | 27% | 46 | 158 | 29% |
| November | 24% | 38 | 169 | 23% |
| December | 24% | 44 | 188 | 23% |
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 | 21% of Europe’s land |
|---|---|
| Light pollution | noticeable light glow |
| Sky-glow index (own, VIIRS) — Darkest spot we found | 11 |
| Sky-glow index (own, VIIRS) — at the official map point | 16 |
| Sky-glow index (own, VIIRS) — median across the area | 12 |
| Darkest spot we found | 42.242, -8.908 (map) — within 2.0 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 | 10.8 | 24% |
| 9 December 2026 | 8–9 December 2026 | 11.5 | 24% |
| 7 January 2027 | 7–8 January 2027 | 11.5 | 24% |
| 6 February 2027 | 6–7 February 2027 | 10.5 | 26% |
| 8 March 2027 | 7–8 March 2027 | 9.3 | 24% |
| 6 April 2027 | 6–7 April 2027 | 7.8 | 22% |
| 6 May 2027 | 5–6 May 2027 | 6.0 | 27% |
| 4 June 2027 | 4–5 June 2027 | 4.7 | 22% |
| 4 July 2027 | 3–4 July 2027 | 4.5 | 33% |
| 2 August 2027 | 1–2 August 2027 | 5.7 | 37% |
| 31 August 2027 | 31 August 2027 – 1 September 2027 | 7.5 | 37% |
| 30 September 2027 | 29–30 September 2027 | 9.0 | 33% |
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 | 45% | 55% | 6.2 | 68° |
| Geminids * | 13–14 December 2026 | 40% | 21% | 9.7 | 81° |
| Geminids * | 14–15 December 2026 | 40% | 29% | 8.8 | 81° |
| Quadrantids | 3–4 January 2027 | 32% | 13% | 11.2 | 66° |
| Lyrids | 22–23 April 2027 | 37% | 95% | 1.2 | 82° |
| Eta Aquariids * | 5–6 May 2027 | 37% | 0% | 7.5 | 21° |
| Eta Aquariids * | 6–7 May 2027 | 33% | 1% | 7.5 | 21° |
| Perseids * | 12–13 August 2027 | 70% | 84% | 3.0 | 66° |
| Perseids * | 13–14 August 2027 | 68% | 91% | 2.0 | 67° |
| Orionids | 21–22 October 2027 | 40% | 58% | 3.7 | 64° |
| Leonids | 17–18 November 2027 | 45% | 82% | 2.0 | 68° |
| Geminids | 14–15 December 2027 | 40% | 97% | 0.0 | 81° |
* 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.