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Katsuyama

36.062° N   136.501° E  ·  130 M
31 /100
PEAK
Nothing usable opens up tonight.
NO USABLE WINDOW · ASTRO DARK 02:00–04:00 · MOON 0%
Transparency
0.49
Seeing
0.77
Cloud
68%
Moon
0%

Poor tonight

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

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
02
03
04
05
31
24
10
0
Low cloud
15%
16%
22%
37%
Mid cloud
45%
44%
58%
61%
High cloud
31%
66%
81%
71%
Transparency
0.47
0.49
0.48
0.47
Seeing
0.73
0.75
0.77
0.74
Moon clear
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
02 Poor · 31/100
Starting from
100
Cloud
−58
Transparency
−9
Seeing
−2
Moonlight
−0
Darkness
−0
Score
31
CLOUD 68% LOW 15% MID 45% HIGH 31% SUN -31.6° MOON -31.3° / 0% WIND 5 TEMP 23°
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.

NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

0204
CLOUD NEVER DROPS BELOW 68%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

0204
CLOUD NEVER DROPS BELOW 68%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

0204
CLOUD NEVER DROPS BELOW 68%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

0204
CLOUD NEVER DROPS BELOW 68%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

0204
CLOUD NEVER DROPS BELOW 68%
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The next week of nights

Tonight · 12 Aug
31
Poor
MOON 0%
Tomorrow · 13 Aug
63
Good
MOON 1%
21:00–23:00
Friday · 14 Aug
46
Fair
MOON 5%
21:00–22:00
Saturday · 15 Aug
29
Poor
MOON 8%
Sunday · 16 Aug
35
Fair
MOON 19%
21:00–22:00
Monday · 17 Aug
34
Poor
MOON 28%
Tuesday · 18 Aug
32
Poor
MOON 37%
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Nearby locations

About this forecast

Conditions for Katsuyama, 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 →