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San Juan de Dios

9.878° N   84.084° W  ·  1207 M
36 /100
PEAK
Marginal, but there is a 1 hour gap from 23:00.
BEST WINDOW 23:00–00:00 · ASTRO DARK 20:00–05:00 · MOON 1%
Transparency
0.46
Seeing
0.93
Cloud
84%
Moon
1%

Fair tonight

Hour by hour, local to San Juan de Dios. Colour encodes the score and nothing else; every other measurement is luminance.

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
18
19
20
21
22
23
00
01
02
03
04
05
06
0
19
18
21
25
36
29
34
35
31
30
3
0
BEST WINDOW
Low cloud
22%
32%
48%
42%
40%
10%
16%
2%
5%
10%
16%
15%
6%
Mid cloud
13%
6%
3%
1%
1%
2%
2%
2%
1%
1%
0%
2%
2%
High cloud
96%
96%
98%
93%
81%
82%
96%
95%
91%
95%
95%
95%
95%
Transparency
0.51
0.46
0.44
0.42
0.43
0.41
0.42
0.39
0.39
0.38
0.38
0.39
0.40
Seeing
0.85
0.86
0.87
0.84
0.85
0.86
0.87
0.89
0.91
0.93
0.93
0.93
0.90
Moon clear
0%
down
down
down
down
down
down
down
down
down
down
down
down
Inspect

Cloud tracks show clear sky — a longer bar is better. The figure inside each track is the raw measurement.

Why this hour scored what it did
18 Clouded out · 0/100
Starting from
100
Cloud
−67
Transparency
−6
Seeing
−1
Moonlight
−0
Darkness
−25
Score
0
CLOUD 98% LOW 22% MID 13% HIGH 96% SUN -1.8° MOON 3.0° / 0% WIND 4 TEMP 22°
Excellent 75+ Good 55+ Fair 35+ Poor 15+ Not worth it Seeing is estimated from surface wind — see how we score.
Tonight's limiting factor
When a clear gap is worth driving for

Ask how long the gap is relative to your setup time and your exposure length. A two-hour gap is a real session for a visual observer and close to worthless for someone doing four-minute subs on a target that needs three hours.

What are you doing tonight?

The same forecast, weighted for the target. Planetary work barely cares about moonlight; long exposures die on high cloud a visual observer would never notice.

NO USABLE WINDOW FOR THIS TARGET TONIGHT

Darkness and moonlight dominate. Faint fuzzies need a genuinely dark sky more than they need steady air.

18202200020406
CLOUD NEVER DROPS BELOW 84%
SET UP 00:30 · OBSERVE 01:00–03:00 · 2H · MEAN 37

Seeing is everything and moonlight is irrelevant. Bright targets punch through twilight, so darkness barely counts.

18202200020406
MOONLIGHT IGNORED FOR THIS TARGET
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Tolerates soft seeing, but high cloud wrecks a wide frame and moonlight raises the background everywhere.

18202200020406
CLOUD NEVER DROPS BELOW 84%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Needs conditions to hold still for hours. Sustained transparency matters more than any single good hour.

18202200020406
CLOUD NEVER DROPS BELOW 84%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Naked eye, whole sky. Total cloud and moonlight are the only things that count.

18202200020406
CLOUD NEVER DROPS BELOW 84%
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The next week of nights

Tonight · 12 Aug
36
Fair
MOON 0%
23:00–00:00
Tomorrow · 13 Aug
63
Good
MOON 3%
23:00–05:00
Friday · 14 Aug
49
Fair
MOON 7%
00:00–01:00
Saturday · 15 Aug
18
Poor
MOON 15%
Sunday · 16 Aug
10
Clouded out
MOON 23%
Monday · 17 Aug
27
Poor
MOON 32%
Tuesday · 18 Aug
43
Fair
MOON 42%
00:00–01:00
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Nearby locations

About this forecast

Conditions for San Juan de Dios, Costa Rica are computed from the MET Norway forecast model for these exact coordinates, combined with sun and moon positions we calculate directly. The score weighs cloud cover by layer, atmospheric transparency, estimated seeing, moonlight and how dark the sky actually gets. Read the full method →