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Isla

18.028° N   95.529° W  ·  67 M
53 /100
PEAK
Marginal, but there is a 5 hours gap from 00:00.
BEST WINDOW 00:00–05:00 · ASTRO DARK 21:00–05:00 · MOON 1%
Transparency
0.22
Seeing
1.00
Cloud
12%
Moon
1%

Fair tonight

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

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
19
20
21
22
23
00
01
02
03
04
05
06
0
39
16
39
24
38
44
48
37
53
50
0
BEST WINDOW
Low cloud
1%
5%
34%
10%
34%
15%
1%
1%
0%
0%
0%
2%
Mid cloud
0%
5%
31%
5%
5%
2%
7%
2%
10%
0%
0%
0%
High cloud
38%
41%
83%
45%
71%
59%
50%
48%
74%
42%
12%
4%
Transparency
0.28
0.10
0.10
0.10
0.10
0.19
0.19
0.20
0.21
0.22
0.22
0.18
Seeing
1.00
1.00
0.89
0.82
0.89
0.96
0.90
1.00
1.00
1.00
1.00
1.00
Moon clear
0%
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
19 Clouded out · 0/100
Starting from
100
Cloud
−21
Transparency
−23
Seeing
−0
Moonlight
−0
Darkness
−56
Score
0
CLOUD 38% LOW 1% MID 0% HIGH 38% SUN -2.9° MOON 2.1° / 0% WIND 1 TEMP 27°
Excellent 75+ Good 55+ Fair 35+ Poor 15+ Not worth it Seeing is estimated from surface wind — see how we score.

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 23:30 · OBSERVE 00:00–03:00 · 3H · MEAN 42

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

192123010305
CLOUD BREAKS 00:00CLOUD RETURNS 03:00
SET UP 23:30 · OBSERVE 00:00–06:00 · 6H · MEAN 57

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

192123010305
CLOUD BREAKS 00:00TWILIGHT BEGINS 06:00MOONLIGHT IGNORED FOR THIS TARGET
SET UP 03:30 · OBSERVE 04:00–06:00 · 2H · MEAN 43

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

192123010305
HIGH CLOUD CLEARS 04:00TWILIGHT BEGINS 06:00
NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

192123010305
CONDITIONS STAY BELOW THE USABLE THRESHOLD
SET UP 03:30 · OBSERVE 04:00–06:00 · 2H · MEAN 49

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

192123010305
HIGH CLOUD CLEARS 04:00TWILIGHT BEGINS 06:00
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The next week of nights

Tonight · 12 Aug
53
Fair
MOON 0%
00:00–05:00
Tomorrow · 13 Aug
53
Fair
MOON 3%
01:00–03:00
Friday · 14 Aug
27
Poor
MOON 7%
Saturday · 15 Aug
0
Clouded out
MOON 15%
Sunday · 16 Aug
44
Fair
MOON 23%
00:00–01:00
Monday · 17 Aug
48
Fair
MOON 32%
00:00–01:00
Tuesday · 18 Aug
27
Poor
MOON 42%
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Nearby locations

About this forecast

Conditions for Isla, Mexico 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 →