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Feira

40.925° N   8.543° W  ·  122 M
46 /100
PEAK
Marginal, but there is a 1 hour gap from 23:00.
BEST WINDOW 23:00–00:00 · ASTRO DARK 23:00–05:00 · MOON 0%
Transparency
0.24
Seeing
1.00
Cloud
14%
Moon
0%

Fair tonight

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

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
21
22
23
00
01
02
03
04
05
06
07
0
39
46
32
25
21
20
21
17
4
0
BEST WINDOW
Low cloud
6%
14%
26%
45%
52%
54%
52%
51%
56%
43%
38%
Mid cloud
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
High cloud
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
Transparency
0.31
0.24
0.20
0.17
0.17
0.18
0.18
0.17
0.16
0.18
0.20
Seeing
0.90
0.89
0.92
0.95
0.99
1.00
1.00
1.00
1.00
1.00
1.00
Moon clear
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
21 Clouded out · 0/100
Starting from
100
Cloud
−9
Transparency
−25
Seeing
−2
Moonlight
−0
Darkness
−64
Score
0
CLOUD 6% LOW 6% MID 0% HIGH 0% SUN -4.7° MOON -1.9° / 0% WIND 3 TEMP 20°
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 22:30 · OBSERVE 23:00–00:00 · 1H · MEAN 46

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

212301030507
ASTRONOMICAL DARK FROM 23:00CLOUD RETURNS 00:00
SET UP 21:30 · OBSERVE 22:00–01:00 · 3H · MEAN 52

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

212301030507
MOONLIGHT IGNORED FOR THIS TARGET
SET UP 21:30 · OBSERVE 22:00–00:00 · 2H · MEAN 39

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

212301030507
CLOUD RETURNS 00:00
NO USABLE WINDOW FOR THIS TARGET TONIGHT

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

212301030507
CONDITIONS STAY BELOW THE USABLE THRESHOLD
SET UP 21:30 · OBSERVE 22:00–00:00 · 2H · MEAN 42

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

212301030507
CLOUD RETURNS 00:00
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The next week of nights

Tonight · 12 Aug
46
Fair
MOON 0%
23:00–00:00
Tomorrow · 13 Aug
50
Fair
MOON 2%
23:00–00:00
Friday · 14 Aug
72
Good
MOON 6%
23:00–06:00
Saturday · 15 Aug
79
Excellent
MOON 13%
01:00–02:00
Sunday · 16 Aug
82
Excellent
MOON 21%
01:00–02:00
Monday · 17 Aug
53
Fair
MOON 30%
01:00–02:00
Tuesday · 18 Aug
75
Excellent
MOON 39%
01:00–02:00
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Nearby locations

About this forecast

Conditions for Feira, Portugal 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 →