13.6 usable nights
10–16 in the middle half of years · 4.7 typically near a dark moon.
341 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at Prescott
October: 23.1 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
Brightened skyBortle classes describe observed sky conditions; this brightness model does not establish a measured Bortle class.20.6–21.1 mag/arcsec²
The short answer
October has been strongest.
It averages 23.1 usable nights, versus 10.9 in July. A typical October lands between 20 and 26 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
12.9 usable nights
11–17 in the middle half of years · 3.8 typically near a dark moon.
287 astronomical-dark hours in an average month
14.2 usable nights
12–17 in the middle half of years · 4.3 typically near a dark moon.
286 astronomical-dark hours in an average month
18.2 usable nights
16–20 in the middle half of years · 5.8 typically near a dark moon.
240 astronomical-dark hours in an average month
21.2 usable nights
19–24 in the middle half of years · 6.9 typically near a dark moon.
203 astronomical-dark hours in an average month
22.3 usable nights
20–26 in the middle half of years · 7.5 typically near a dark moon.
180 astronomical-dark hours in an average month
10.9 usable nights
8–14 in the middle half of years · 3.8 typically near a dark moon.
190 astronomical-dark hours in an average month
13.5 usable nights
12–15 in the middle half of years · 3.7 typically near a dark moon.
241 astronomical-dark hours in an average month
20.4 usable nights
18–22 in the middle half of years · 7.3 typically near a dark moon.
256 astronomical-dark hours in an average month
23.1 usable nights
20–26 in the middle half of years · 7.8 typically near a dark moon.
310 astronomical-dark hours in an average month
17.8 usable nights
16–20 in the middle half of years · 6.3 typically near a dark moon.
327 astronomical-dark hours in an average month
12.7 usable nights
8–17 in the middle half of years · 4.3 typically near a dark moon.
357 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.