11.3 usable nights
10–13 in the middle half of years · 4.0 typically near a dark moon.
341 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at San Angelo
October: 17.2 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.19.4–20.1 mag/arcsec²
The short answer
October has been strongest.
It averages 17.2 usable nights, versus 9.2 in February. A typical October lands between 13 and 22 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
9.2 usable nights
7–12 in the middle half of years · 2.9 typically near a dark moon.
284 astronomical-dark hours in an average month
10.5 usable nights
7–14 in the middle half of years · 3.1 typically near a dark moon.
293 astronomical-dark hours in an average month
11.3 usable nights
9–13 in the middle half of years · 4.2 typically near a dark moon.
240 astronomical-dark hours in an average month
9.8 usable nights
6–13 in the middle half of years · 3.0 typically near a dark moon.
225 astronomical-dark hours in an average month
12.7 usable nights
10–15 in the middle half of years · 3.9 typically near a dark moon.
180 astronomical-dark hours in an average month
14.6 usable nights
12–18 in the middle half of years · 5.0 typically near a dark moon.
204 astronomical-dark hours in an average month
14.6 usable nights
11–17 in the middle half of years · 5.0 typically near a dark moon.
248 astronomical-dark hours in an average month
15.2 usable nights
13–17 in the middle half of years · 5.4 typically near a dark moon.
262 astronomical-dark hours in an average month
17.2 usable nights
13–22 in the middle half of years · 6.5 typically near a dark moon.
310 astronomical-dark hours in an average month
13.7 usable nights
10–17 in the middle half of years · 4.0 typically near a dark moon.
324 astronomical-dark hours in an average month
10.4 usable nights
8–12 in the middle half of years · 3.5 typically near a dark moon.
341 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.