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San Antonio

-25.421° S   57.547° W  ·  123 M
72 /100
PEAK
Worth setting up — 3 hours of workable sky from 20:00.
BEST WINDOW 20:00–23:00 · ASTRO DARK 20:00–07:00 · MOON 0%
Transparency
0.40
Seeing
1.00
Cloud
3%
Moon
0%

Good tonight

Hour by hour, local to San Antonio. 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
07
0
8
72
68
38
28
28
14
27
22
29
13
5
0
BEST WINDOW
Low cloud
0%
0%
0%
0%
0%
0%
0%
0%
2%
6%
1%
2%
2%
0%
Mid cloud
0%
0%
0%
0%
0%
12%
13%
56%
7%
20%
17%
60%
100%
100%
High cloud
0%
3%
7%
13%
85%
99%
99%
99%
98%
100%
80%
93%
34%
0%
Transparency
0.49
0.40
0.38
0.36
0.32
0.30
0.29
0.10
0.23
0.22
0.10
0.10
0.20
0.21
Seeing
1.00
1.00
1.00
0.93
0.92
0.87
0.86
0.92
0.73
0.76
0.79
0.80
0.84
0.81
Moon clear
0%
down
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
−0
Transparency
−20
Seeing
−0
Moonlight
−0
Darkness
−80
Score
0
CLOUD 0% LOW 0% MID 0% HIGH 0% SUN 5.7° MOON 8.6° / 0% WIND 1 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.

SET UP 19:30 · OBSERVE 20:00–23:00 · 3H · MEAN 58

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

18202200020406
ASTRONOMICAL DARK FROM 20:00
SET UP 18:30 · OBSERVE 19:00–23:00 · 4H · MEAN 64

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

18202200020406
MOONLIGHT IGNORED FOR THIS TARGET
SET UP 19:30 · OBSERVE 20:00–22:00 · 2H · MEAN 65

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

18202200020406
ASTRONOMICAL DARK FROM 20:00CLOUD RETURNS 22:00
SET UP 19:30 · OBSERVE 20:00–22:00 · 2H · MEAN 56

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

18202200020406
ASTRONOMICAL DARK FROM 20:00CLOUD RETURNS 22:00
SET UP 19:30 · OBSERVE 20:00–22:00 · 2H · MEAN 73

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

18202200020406
ASTRONOMICAL DARK FROM 20:00CLOUD RETURNS 22:00
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The next week of nights

Tonight · 12 Aug
72
Good
MOON 0%
20:00–23:00
Tomorrow · 13 Aug
67
Good
MOON 3%
01:00–07:00
Friday · 14 Aug
47
Fair
MOON 7%
22:00–23:00
Saturday · 15 Aug
58
Good
MOON 15%
21:00–22:00
Sunday · 16 Aug
82
Excellent
MOON 23%
03:00–04:00
Monday · 17 Aug
50
Fair
MOON 32%
21:00–22:00
Tuesday · 18 Aug
5
Clouded out
MOON 42%
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Nearby locations

About this forecast

Conditions for San Antonio, Paraguay 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 →