6.7 usable nights
4–8 in the middle half of years · 2.3 typically near a dark moon.
327 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at Largo
May: 13.3 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.18.5–19.2 mag/arcsec²
The short answer
May has been strongest.
It averages 13.3 usable nights, versus 2.1 in August. A typical May lands between 12 and 15 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
9.4 usable nights
9–11 in the middle half of years · 2.6 typically near a dark moon.
283 astronomical-dark hours in an average month
11.8 usable nights
10–14 in the middle half of years · 4.3 typically near a dark moon.
298 astronomical-dark hours in an average month
10.9 usable nights
9–13 in the middle half of years · 3.3 typically near a dark moon.
242 astronomical-dark hours in an average month
13.3 usable nights
12–15 in the middle half of years · 4.0 typically near a dark moon.
248 astronomical-dark hours in an average month
4.8 usable nights
4–7 in the middle half of years · 1.9 typically near a dark moon.
221 astronomical-dark hours in an average month
2.3 usable nights
1–3 in the middle half of years · 0.9 typically near a dark moon.
235 astronomical-dark hours in an average month
2.1 usable nights
1–3 in the middle half of years · 0.8 typically near a dark moon.
248 astronomical-dark hours in an average month
7.0 usable nights
5–9 in the middle half of years · 2.3 typically near a dark moon.
270 astronomical-dark hours in an average month
12.4 usable nights
11–14 in the middle half of years · 4.2 typically near a dark moon.
310 astronomical-dark hours in an average month
8.5 usable nights
5–12 in the middle half of years · 2.5 typically near a dark moon.
318 astronomical-dark hours in an average month
7.3 usable nights
6–9 in the middle half of years · 2.4 typically near a dark moon.
321 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.