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Siem Reap

13.362° N   103.861° E  ·  18 M
65 /100
PEAK
Worth setting up — 5 hours of workable sky from 00:00.
BEST WINDOW 00:00–05:00 · ASTRO DARK 00:00–05:00 · MOON 0%
Transparency
0.40
Seeing
0.90
Cloud
9%
Moon
0%

Good tonight

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

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
00
01
02
03
04
05
06
35
43
37
57
65
39
0
BEST WINDOW
Low cloud
1%
0%
0%
0%
0%
0%
0%
Mid cloud
9%
9%
17%
16%
6%
0%
1%
High cloud
87%
66%
72%
12%
8%
9%
6%
Transparency
0.40
0.38
0.36
0.35
0.34
0.34
0.34
Seeing
0.86
0.89
0.90
0.89
0.90
0.87
0.86
Moon clear
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
00 Fair · 35/100
Starting from
100
Cloud
−52
Transparency
−12
Seeing
−1
Moonlight
−0
Darkness
−0
Score
35
CLOUD 88% LOW 1% MID 9% HIGH 87% SUN -61.6° MOON -60.5° / 0% WIND 3 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 00:30 · OBSERVE 01:00–05:00 · 4H · MEAN 50

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

00020406
HIGH CLOUD CLEARS 01:00TWILIGHT BEGINS 05:00
SET UP 23:30 · OBSERVE 00:00–06:00 · 6H · MEAN 56

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

00020406
TWILIGHT BEGINS 06:00MOONLIGHT IGNORED FOR THIS TARGET
SET UP 02:30 · OBSERVE 03:00–05:00 · 2H · MEAN 57

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

00020406
HIGH CLOUD CLEARS 03:00TWILIGHT BEGINS 05:00
SET UP 02:30 · OBSERVE 03:00–05:00 · 2H · MEAN 47

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

00020406
HIGH CLOUD CLEARS 03:00TWILIGHT BEGINS 05:00
SET UP 02:30 · OBSERVE 03:00–05:00 · 2H · MEAN 64

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

00020406
HIGH CLOUD CLEARS 03:00TWILIGHT BEGINS 05:00
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The next week of nights

Tonight · 12 Aug
65
Good
MOON 0%
00:00–05:00
Tomorrow · 13 Aug
50
Fair
MOON 1%
20:00–23:00
Friday · 14 Aug
30
Poor
MOON 5%
Saturday · 15 Aug
13
Clouded out
MOON 10%
Sunday · 16 Aug
16
Poor
MOON 19%
Monday · 17 Aug
3
Clouded out
MOON 28%
Tuesday · 18 Aug
3
Clouded out
MOON 37%
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Nearby locations

About this forecast

Conditions for Siem Reap, Cambodia 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 →