GoodSeeing
Home › Locations › Gresham

Gresham

45.498° N   122.431° W  ·  96 M
71 /100
PEAK
Worth setting up — 4 hours of workable sky from 23:00.
BEST WINDOW 23:00–03:00 · ASTRO DARK 23:00–05:00 · MOON 1%
Transparency
0.60
Seeing
1.00
Cloud
9%
Moon
1%

Good tonight

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

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
20
21
22
23
00
01
02
03
04
05
06
0
4
55
71
69
65
56
27
18
5
0
BEST WINDOW
Low cloud
14%
20%
11%
9%
9%
13%
23%
63%
75%
84%
97%
Mid cloud
1%
1%
0%
0%
0%
0%
0%
0%
0%
0%
0%
High cloud
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
Transparency
0.70
0.60
0.55
0.48
0.42
0.37
0.34
0.32
0.27
0.27
0.29
Seeing
0.81
0.83
0.88
0.91
0.99
1.00
1.00
1.00
1.00
1.00
1.00
Moon clear
0%
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
20 Clouded out · 0/100
Starting from
100
Cloud
−15
Transparency
−10
Seeing
−4
Moonlight
−0
Darkness
−72
Score
0
CLOUD 14% LOW 14% MID 1% HIGH 0% SUN 2.9° MOON 6.4° / 0% WIND 4 TEMP 22°
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 21:30 · OBSERVE 22:00–03:00 · 5H · MEAN 62

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

202200020406
CLOUD RETURNS 03:00
SET UP 21:30 · OBSERVE 22:00–03:00 · 5H · MEAN 75

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

202200020406
CLOUD RETURNS 03:00MOONLIGHT IGNORED FOR THIS TARGET
SET UP 21:30 · OBSERVE 22:00–03:00 · 5H · MEAN 60

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

202200020406
CLOUD RETURNS 03:00
SET UP 21:30 · OBSERVE 22:00–03:00 · 5H · MEAN 51

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

202200020406
CLOUD RETURNS 03:00
SET UP 21:30 · OBSERVE 22:00–03:00 · 5H · MEAN 65

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

202200020406
CLOUD RETURNS 03:00
Advertisement
Reserved

The next week of nights

Tonight · 12 Aug
71
Good
MOON 1%
23:00–03:00
Tomorrow · 13 Aug
81
Excellent
MOON 3%
23:00–05:00
Friday · 14 Aug
81
Excellent
MOON 7%
23:00–00:00
Saturday · 15 Aug
85
Excellent
MOON 17%
23:00–00:00
Sunday · 16 Aug
39
Fair
MOON 25%
23:00–00:00
Monday · 17 Aug
27
Poor
MOON 35%
Tuesday · 18 Aug
76
Excellent
MOON 44%
23:00–00:00
Advertisement
Reserved

Nearby locations

About this forecast

Conditions for Gresham, Oregon, United States 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 →