12.8 usable nights
10–17 in the middle half of years · 4.4 typically near a dark moon.
341 astronomical-dark hours in an average month
20-year trip-planning baseline
When to plan an observing trip to Santa Barbara
August: 23.9 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.20.3–20.9 mag/arcsec²
The short answer
August has been strongest.
It averages 23.9 usable nights, versus 11.8 in March. A typical August lands between 21 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
12.5 usable nights
8–18 in the middle half of years · 4.1 typically near a dark moon.
287 astronomical-dark hours in an average month
11.8 usable nights
8–16 in the middle half of years · 3.4 typically near a dark moon.
287 astronomical-dark hours in an average month
15.8 usable nights
13–18 in the middle half of years · 5.3 typically near a dark moon.
240 astronomical-dark hours in an average month
17.3 usable nights
15–20 in the middle half of years · 5.5 typically near a dark moon.
203 astronomical-dark hours in an average month
17.9 usable nights
15–22 in the middle half of years · 6.1 typically near a dark moon.
180 astronomical-dark hours in an average month
20.6 usable nights
18–22 in the middle half of years · 6.8 typically near a dark moon.
190 astronomical-dark hours in an average month
23.9 usable nights
21–26 in the middle half of years · 7.5 typically near a dark moon.
241 astronomical-dark hours in an average month
21.6 usable nights
20–23 in the middle half of years · 7.9 typically near a dark moon.
256 astronomical-dark hours in an average month
20.4 usable nights
18–23 in the middle half of years · 7.0 typically near a dark moon.
310 astronomical-dark hours in an average month
16.5 usable nights
14–19 in the middle half of years · 5.6 typically near a dark moon.
327 astronomical-dark hours in an average month
11.9 usable nights
6–17 in the middle half of years · 4.3 typically near a dark moon.
356 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.