1.8 usable nights
0–3 in the middle half of years · 0.6 typically near a dark moon.
355 astronomical-dark hours in an average month
20-year trip-planning baseline
When to plan an observing trip to Bend
July: 21.8 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.20.1–20.7 mag/arcsec²
The short answer
July has been strongest.
It averages 21.8 usable nights, versus 1.7 in December. A typical July lands between 20 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
3.0 usable nights
1–5 in the middle half of years · 0.8 typically near a dark moon.
292 astronomical-dark hours in an average month
3.0 usable nights
2–4 in the middle half of years · 1.0 typically near a dark moon.
270 astronomical-dark hours in an average month
4.3 usable nights
2–6 in the middle half of years · 1.6 typically near a dark moon.
210 astronomical-dark hours in an average month
6.5 usable nights
3–9 in the middle half of years · 2.5 typically near a dark moon.
156 astronomical-dark hours in an average month
10.5 usable nights
9–12 in the middle half of years · 3.8 typically near a dark moon.
120 astronomical-dark hours in an average month
21.8 usable nights
20–24 in the middle half of years · 7.2 typically near a dark moon.
134 astronomical-dark hours in an average month
19.3 usable nights
17–21 in the middle half of years · 7.3 typically near a dark moon.
196 astronomical-dark hours in an average month
13.3 usable nights
11–16 in the middle half of years · 4.2 typically near a dark moon.
246 astronomical-dark hours in an average month
9.3 usable nights
6–12 in the middle half of years · 2.5 typically near a dark moon.
304 astronomical-dark hours in an average month
2.9 usable nights
2–4 in the middle half of years · 0.8 typically near a dark moon.
332 astronomical-dark hours in an average month
1.7 usable nights
0–3 in the middle half of years · 0.3 typically near a dark moon.
372 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.