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Suwa

36.038° N   138.113° E  ·  762 M
22 /100
PEAK
Nothing usable opens up tonight.
NO USABLE WINDOW · ASTRO DARK 02:00–04:00 · MOON 0%
Transparency
0.23
Seeing
1.00
Cloud
44%
Moon
0%

Poor tonight

Hour by hour, local to Suwa. 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
22
19
19
0
Low cloud
38%
32%
29%
30%
Mid cloud
1%
2%
2%
1%
High cloud
68%
89%
21%
63%
Transparency
0.23
0.23
0.23
0.21
Seeing
1.00
1.00
1.00
1.00
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 · 22/100
Starting from
100
Cloud
−69
Transparency
−10
Seeing
−0
Moonlight
−0
Darkness
−0
Score
22
CLOUD 80% LOW 38% MID 1% HIGH 68% SUN -30.8° MOON -30.6° / 0% WIND 2 TEMP 17°
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 44%
SET UP 03:30 · OBSERVE 04:00–05:00 · 1H · MEAN 36

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

0204
HIGH CLOUD CLEARS 04:00CLOUD RETURNS 05:00MOONLIGHT IGNORED FOR THIS TARGET
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 44%
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 44%
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 44%
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The next week of nights

Tonight · 12 Aug
22
Poor
MOON 0%
Tomorrow · 13 Aug
57
Good
MOON 1%
21:00–00:00
Friday · 14 Aug
48
Fair
MOON 5%
21:00–22:00
Saturday · 15 Aug
46
Fair
MOON 8%
21:00–22:00
Sunday · 16 Aug
60
Good
MOON 19%
21:00–22:00
Monday · 17 Aug
30
Poor
MOON 28%
Tuesday · 18 Aug
31
Poor
MOON 37%
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Nearby locations

About this forecast

Conditions for Suwa, 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 →