11.4 usable nights
8–14 in the middle half of years · 3.5 typically near a dark moon.
342 astronomical-dark hours in an average month
20-year trip-planning baseline
When to plan an observing trip to Santa Fe
October: 17.7 usable nights on average. A regional planning baseline, not a forecast for your trip.
Site darkness · modelled, not measured
Brightened skyBortle classes describe observed sky conditions; this brightness model does not establish a measured Bortle class.20.2–20.8 mag/arcsec²
The short answer
October has been strongest.
It averages 17.7 usable nights, versus 6.2 in July. A typical October lands between 16 and 21 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
10.1 usable nights
8–12 in the middle half of years · 3.1 typically near a dark moon.
288 astronomical-dark hours in an average month
10.9 usable nights
9–13 in the middle half of years · 2.9 typically near a dark moon.
284 astronomical-dark hours in an average month
12.2 usable nights
11–12 in the middle half of years · 3.6 typically near a dark moon.
240 astronomical-dark hours in an average month
13.7 usable nights
10–16 in the middle half of years · 4.7 typically near a dark moon.
196 astronomical-dark hours in an average month
12.1 usable nights
8–16 in the middle half of years · 3.6 typically near a dark moon.
180 astronomical-dark hours in an average month
6.2 usable nights
4–7 in the middle half of years · 2.5 typically near a dark moon.
186 astronomical-dark hours in an average month
7.8 usable nights
6–11 in the middle half of years · 2.5 typically near a dark moon.
237 astronomical-dark hours in an average month
14.6 usable nights
12–16 in the middle half of years · 5.5 typically near a dark moon.
253 astronomical-dark hours in an average month
17.7 usable nights
16–21 in the middle half of years · 6.3 typically near a dark moon.
310 astronomical-dark hours in an average month
15.3 usable nights
13–17 in the middle half of years · 4.8 typically near a dark moon.
327 astronomical-dark hours in an average month
10.9 usable nights
8–13 in the middle half of years · 3.6 typically near a dark moon.
360 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.