2.6 usable nights
1–3 in the middle half of years · 0.8 typically near a dark moon.
353 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at Twin Falls
July: 16.6 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
Brightened skyBortle classes describe observed sky conditions; this brightness model does not establish a measured Bortle class.20.0–20.6 mag/arcsec²
The short answer
July has been strongest.
It averages 16.6 usable nights, versus 1.9 in December. A typical July lands between 14 and 20 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
2.9 usable nights
1–3 in the middle half of years · 1.0 typically near a dark moon.
291 astronomical-dark hours in an average month
5.3 usable nights
4–6 in the middle half of years · 1.6 typically near a dark moon.
273 astronomical-dark hours in an average month
7.3 usable nights
6–8 in the middle half of years · 2.5 typically near a dark moon.
216 astronomical-dark hours in an average month
7.5 usable nights
5–10 in the middle half of years · 2.5 typically near a dark moon.
168 astronomical-dark hours in an average month
11.9 usable nights
11–14 in the middle half of years · 4.3 typically near a dark moon.
120 astronomical-dark hours in an average month
16.6 usable nights
14–20 in the middle half of years · 5.3 typically near a dark moon.
147 astronomical-dark hours in an average month
15.0 usable nights
13–19 in the middle half of years · 5.7 typically near a dark moon.
203 astronomical-dark hours in an average month
14.8 usable nights
13–17 in the middle half of years · 5.0 typically near a dark moon.
247 astronomical-dark hours in an average month
11.1 usable nights
9–13 in the middle half of years · 3.0 typically near a dark moon.
305 astronomical-dark hours in an average month
6.0 usable nights
3–8 in the middle half of years · 2.0 typically near a dark moon.
330 astronomical-dark hours in an average month
1.9 usable nights
0–3 in the middle half of years · 0.5 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.