6.8 usable nights
3–10 in the middle half of years · 2.0 typically near a dark moon.
349 astronomical-dark hours in an average month
20-year trip-planning baseline
When to plan an observing trip to Reno
August: 21.3 usable nights on average. A regional planning baseline, not a forecast for your trip.
Site darkness · modelled, not measured
Bright skyBortle classes describe observed sky conditions; this brightness model does not establish a measured Bortle class.19.1–19.8 mag/arcsec²
The short answer
August has been strongest.
It averages 21.3 usable nights, versus 5.8 in December. A typical August lands between 18 and 24 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
7.5 usable nights
4–11 in the middle half of years · 2.5 typically near a dark moon.
290 astronomical-dark hours in an average month
8.2 usable nights
7–10 in the middle half of years · 1.9 typically near a dark moon.
278 astronomical-dark hours in an average month
9.8 usable nights
7–12 in the middle half of years · 3.0 typically near a dark moon.
230 astronomical-dark hours in an average month
11.8 usable nights
9–16 in the middle half of years · 4.0 typically near a dark moon.
186 astronomical-dark hours in an average month
16.9 usable nights
14–20 in the middle half of years · 5.7 typically near a dark moon.
163 astronomical-dark hours in an average month
20.8 usable nights
19–24 in the middle half of years · 6.8 typically near a dark moon.
181 astronomical-dark hours in an average month
21.3 usable nights
18–24 in the middle half of years · 6.5 typically near a dark moon.
217 astronomical-dark hours in an average month
20.5 usable nights
18–22 in the middle half of years · 7.2 typically near a dark moon.
250 astronomical-dark hours in an average month
17.2 usable nights
13–21 in the middle half of years · 5.5 typically near a dark moon.
307 astronomical-dark hours in an average month
10.2 usable nights
9–11 in the middle half of years · 3.5 typically near a dark moon.
329 astronomical-dark hours in an average month
5.8 usable nights
3–8 in the middle half of years · 1.9 typically near a dark moon.
367 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.