1.6 usable nights
0–3 in the middle half of years · 0.3 typically near a dark moon.
358 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at South Hill
August: 12.7 usable nights on average. Use this seasonal climate baseline to choose a month, then use the live forecast to choose a night.
Site darkness · modelled, not measured
Bright skyBortle classes describe observed sky conditions; this brightness model does not establish a measured Bortle class.19.0–19.7 mag/arcsec²
The short answer
August has been strongest.
It averages 12.7 usable nights, versus 0.0 in June. A typical August lands between 10 and 16 usable nights.
Record2005–2024 · 20 complete years
Usable nightAt least 3 astronomical-dark hours and NASA POWER nighttime cloud ≤30%
Dark-moon nightUsable night with ≤25% illumination at local solar midnight
ResolutionCERES SYN1deg 1° cloud grid; regional climate, not a campsite guarantee
Seasonal fingerprint
Usable nights by month
Month by month
2.1 usable nights
1–3 in the middle half of years · 0.7 typically near a dark moon.
292 astronomical-dark hours in an average month
2.2 usable nights
1–3 in the middle half of years · 0.6 typically near a dark moon.
265 astronomical-dark hours in an average month
2.6 usable nights
1–4 in the middle half of years · 0.9 typically near a dark moon.
198 astronomical-dark hours in an average month
4.7 usable nights
3–6 in the middle half of years · 2.1 typically near a dark moon.
132 astronomical-dark hours in an average month
0.0 usable nights
0–0 in the middle half of years · 0.0 typically near a dark moon.
60 astronomical-dark hours in an average month
10.1 usable nights
6–12 in the middle half of years · 3.4 typically near a dark moon.
101 astronomical-dark hours in an average month
12.7 usable nights
10–16 in the middle half of years · 5.5 typically near a dark moon.
175 astronomical-dark hours in an average month
9.1 usable nights
6–12 in the middle half of years · 2.8 typically near a dark moon.
241 astronomical-dark hours in an average month
5.0 usable nights
2–7 in the middle half of years · 0.8 typically near a dark moon.
302 astronomical-dark hours in an average month
2.3 usable nights
0–4 in the middle half of years · 0.5 typically near a dark moon.
336 astronomical-dark hours in an average month
1.8 usable nights
0–3 in the middle half of years · 0.4 typically near a dark moon.
372 astronomical-dark hours in an average month
Use the baseline honestly
Climate chooses the month. Forecasts choose the night.
The cloud product is a roughly 1° regional grid. It can reveal seasonality, but it cannot know a mountain ridge, valley fog pocket, locked gate, smoke event or the exact sky you will get.
Source: NASA POWER daily data, parameter CLOUD_AMT_NIGHT from the CERES SYN1deg cloud product. GoodSeeing calculates astronomical darkness and lunar illumination independently for each place.