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Yamaguchi

34.183° N   131.467° E  ·  157 M
65 /100
PEAK
Worth setting up — 4 hours of workable sky from 01:00.
BEST WINDOW 01:00–05:00 · ASTRO DARK 01:00–05:00 · MOON 0%
Transparency
0.23
Seeing
1.00
Cloud
6%
Moon
0%

Good tonight

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

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
01
02
03
04
05
06
50
61
59
65
7
0
BEST WINDOW
Low cloud
27%
8%
5%
4%
9%
6%
Mid cloud
2%
6%
12%
2%
2%
2%
High cloud
0%
0%
0%
0%
0%
0%
Transparency
0.23
0.23
0.23
0.22
0.20
0.19
Seeing
1.00
1.00
1.00
1.00
1.00
1.00
Moon clear
down
down
down
down
down
0%
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
01 Fair · 50/100
Starting from
100
Cloud
−28
Transparency
−22
Seeing
−0
Moonlight
−0
Darkness
−0
Score
50
CLOUD 28% LOW 27% MID 2% HIGH 0% SUN -39.9° MOON -38.9° / 0% WIND 1 TEMP 21°
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 59

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

010305
TWILIGHT BEGINS 05:00
SET UP 00:30 · OBSERVE 01:00–06:00 · 5H · MEAN 67

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

010305
TWILIGHT BEGINS 06:00MOONLIGHT IGNORED FOR THIS TARGET
SET UP 00:30 · OBSERVE 01:00–05:00 · 4H · MEAN 54

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

010305
TWILIGHT BEGINS 05:00
SET UP 00:30 · OBSERVE 01:00–05:00 · 4H · MEAN 44

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

010305
TWILIGHT BEGINS 05:00
SET UP 00:30 · OBSERVE 01:00–05:00 · 4H · MEAN 61

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

010305
TWILIGHT BEGINS 05:00
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The next week of nights

Tonight · 12 Aug
65
Good
MOON 0%
01:00–05:00
Tomorrow · 13 Aug
51
Fair
MOON 1%
21:00–00:00
Friday · 14 Aug
28
Poor
MOON 5%
Saturday · 15 Aug
31
Poor
MOON 8%
Sunday · 16 Aug
15
Poor
MOON 19%
Monday · 17 Aug
1
Clouded out
MOON 28%
Tuesday · 18 Aug
58
Good
MOON 37%
03:00–04:00
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Nearby locations

About this forecast

Conditions for Yamaguchi, Japan 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 →