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Night Forecast

Weather
Observing Conditions.

Hour-by-hour night-window forecast built for observing, imaging, and planning around clouds, rain risk, visibility, dew spread, wind, humidity, and your active rig.

Good conditions
Observing Outlook

Good observing conditions expected

Night-window score reflects clouds, rain risk, visibility, dew risk, wind, and humidity. Clouds 64%, rain risk 29%, wind 8 mph.

66/100 Good Best: 3 AM – 6 AM
Choose Forecast Date
Su M T W Th F Sa
16 17 18 19 20 21 22 23 24 25 26 27 28 29
Forecast Location Chicago Area 41.878100, -87.629800 41.87810, -87.62980
Overall 66 Good
Clouds 64% Partly cloudy
Rain Risk 29% Max overnight
Visibility 10 mi Fair
Wind 8 mph Gusts 18 mph
Observatory Intelligence

No default rig selected

Add your telescope, focal length, and mount to unlock equipment-specific weather guidance.

Ephemeris can interpret wind, cloud layers, humidity, and dew risk differently for widefield, mid-focal, and long-focal-length setups.

Best Use Tonight General observing guidance
Avoid Tonight Rig-specific guidance unavailable
Improves After 3 AM
•
Visual Observing

General sky conditions are available now.

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Deep Sky Imaging

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Why does rig data matter for imaging? →
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Planetary / Lunar

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Forecast Confidence

Low Confidence

Conditions appear changeable enough that the observing window may shift.

3 forecast source active
  • Forecast sources active: 2
  • Alert sources active: 1
  • Forecast models disagree during multiple observing hours
  • Cloud cover changes sharply during the night
Hour-by-Hour

Observing Window

2026-08-21 7 PM → next morning 6 AM
Time Score Outlook Clouds Low Mid High Rain Visibility Dew Spread Wind Humidity
8/21 - 7 PM 68 Good 92% 92% 0% 59% 13% 16.2 mi 11.3°F ? 4 mph 68%
8/21 - 8 PM 50 Fair 93% 47% 93% 77% 16% 11.4 mi 6.5°F ? 5 mph 80%
8/21 - 9 PM 65 Good 84% 3% 84% 84% 19% 12.9 mi 8°F ? 6 mph 76%
8/21 - 10 PM 45 Fair 75% 63% 38% 75% 19% 9.8 mi 4.3°F ? 12 mph 86%
8/21 - 11 PM 52 Fair 95% 11% 39% 95% 27% 8.6 mi 2.7°F ? 5 mph 91%
8/22 - 12 AM 72 Good 95% 1% 0% 95% 29% 10.8 mi 5.7°F ? 11 mph 82%
8/22 - 1 AM 71 Good 99% 5% 0% 99% 17% 8.9 mi 3.3°F ? 7 mph 89%
8/22 - 2 AM 73 Good 100% 10% 0% 100% 10% 9.1 mi 3.3°F ? 6 mph 89%
8/22 - 3 AM 75 Good 1% 1% 0% 0% 6% 8.8 mi 3.3°F ? 9 mph 89%
8/22 - 4 AM 73 Good 9% 9% 0% 0% 4% 8.1 mi 2.4°F ? 10 mph 92%
8/22 - 5 AM 70 Good 17% 17% 0% 0% 1% 7.8 mi 2.1°F ? 9 mph 93%
8/22 - 6 AM 72 Good 12% 12% 0% 0% 1% 7.6 mi 1.8°F ? 6 mph 94%
Cloud Timeline

Cloud Cover by Hour

Each hour shows total cloud cover plus the split between low, mid, and high cloud layers.

Low Mid High
7 PM
92% Total
Low
92%
Mid
0%
High
59%
8 PM
93% Total
Low
47%
Mid
93%
High
77%
9 PM
84% Total
Low
3%
Mid
84%
High
84%
10 PM
75% Total
Low
63%
Mid
38%
High
75%
11 PM
95% Total
Low
11%
Mid
39%
High
95%
12 AM
95% Total
Low
1%
Mid
0%
High
95%
1 AM
99% Total
Low
5%
Mid
0%
High
99%
2 AM
100% Total
Low
10%
Mid
0%
High
100%
3 AM
1% Total
Low
1%
Mid
0%
High
0%
4 AM
9% Total
Low
9%
Mid
0%
High
0%
5 AM
17% Total
Low
17%
Mid
0%
High
0%
6 AM
12% Total
Low
12%
Mid
0%
High
0%
Why this score?

Limiting Factors

Humidity 86% Major limiter
Dew Spread 4.6°F Major limiter
Visibility 10 mi High impact
High Clouds 57% High impact
Low Clouds 23% Moderate impact
Source Comparison

Forecast Sources

MVP starts with Open-Meteo; additional sources will improve confidence scoring.
Source Clouds Rain Humidity Wind Status
Open-Meteo 64% 29% 86% 8 mph Primary forecast
Tomorrow.io -- -- -- -- Secondary forecast active
National Weather Service -- -- -- -- Active alert cap: 20