13.1 usable nights
11–18 in the middle half of years · 4.1 typically near a dark moon.
341 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at Anthem
October: 22.1 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.19.5–20.2 mag/arcsec²
The short answer
October has been strongest.
It averages 22.1 usable nights, versus 8.8 in July. A typical October lands between 19 and 27 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
12.8 usable nights
10–17 in the middle half of years · 3.8 typically near a dark moon.
287 astronomical-dark hours in an average month
14.6 usable nights
13–17 in the middle half of years · 4.5 typically near a dark moon.
288 astronomical-dark hours in an average month
17.9 usable nights
17–20 in the middle half of years · 5.7 typically near a dark moon.
240 astronomical-dark hours in an average month
20.9 usable nights
18–23 in the middle half of years · 6.8 typically near a dark moon.
207 astronomical-dark hours in an average month
20.8 usable nights
17–25 in the middle half of years · 6.9 typically near a dark moon.
180 astronomical-dark hours in an average month
8.8 usable nights
5–12 in the middle half of years · 3.3 typically near a dark moon.
192 astronomical-dark hours in an average month
11.5 usable nights
8–15 in the middle half of years · 3.5 typically near a dark moon.
242 astronomical-dark hours in an average month
19.6 usable nights
17–22 in the middle half of years · 6.8 typically near a dark moon.
257 astronomical-dark hours in an average month
22.1 usable nights
19–27 in the middle half of years · 7.5 typically near a dark moon.
310 astronomical-dark hours in an average month
17.5 usable nights
16–18 in the middle half of years · 5.8 typically near a dark moon.
326 astronomical-dark hours in an average month
12.1 usable nights
8–15 in the middle half of years · 4.4 typically near a dark moon.
354 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.