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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.

Excellent conditions
Observing Outlook

Excellent observing conditions expected

Night-window score reflects clouds, rain risk, visibility, dew risk, wind, and humidity. Clouds 2%, rain risk 5%, wind 5 mph.

89/100 Excellent Best: 7 PM – 9 PM
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 89 Excellent
Clouds 2% Clear
Rain Risk 5% Max overnight
Visibility 15 mi Good
Wind 5 mph Gusts 7 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 7 PM
•
Visual Observing

General sky conditions are available now.

What makes an observing forecast different? →
•
Deep Sky Imaging

Add a default rig for tailored guidance.

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

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Why does focal length change weather sensitivity? →
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Forecast Confidence

High Confidence

Forecast conditions are relatively stable across the night window.

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

2026-08-27 7 PM → next morning 6 AM
Time Score Outlook Clouds Low Mid High Rain Visibility Dew Spread Wind Humidity
8/27 - 7 PM 91 Excellent 0% 0% 0% 0% 4% 15 mi 12°F ? 6 mph 66%
8/27 - 8 PM 91 Excellent 0% 0% 0% 0% 5% 15 mi 10.3°F ? 5 mph 70%
8/27 - 9 PM 88 Excellent 0% 0% 0% 0% 5% 15 mi 9.1°F ? 5 mph 73%
8/27 - 10 PM 88 Excellent 0% 0% 0% 0% 5% 15 mi 8.3°F ? 5 mph 75%
8/27 - 11 PM 88 Excellent 1% 0% 0% 1% 5% 15 mi 8.3°F ? 5 mph 75%
8/28 - 12 AM 88 Excellent 2% 0% 0% 2% 5% 15 mi 8.7°F ? 5 mph 74%
8/28 - 1 AM 88 Excellent 2% 0% 0% 2% 5% 15 mi 9.1°F ? 5 mph 73%
8/28 - 2 AM 88 Excellent 0% 0% 0% 0% 4% 15 mi 8.6°F ? 5 mph 74%
8/28 - 3 AM 89 Excellent 0% 0% 0% 0% 4% 15 mi 8.2°F ? 4 mph 75%
8/28 - 4 AM 89 Excellent 0% 0% 0% 0% 4% 15 mi 7.5°F ? 4 mph 77%
8/28 - 5 AM 87 Excellent 7% 0% 0% 7% 4% 15 mi 6.4°F ? 4 mph 80%
8/28 - 6 AM 87 Excellent 17% 0% 0% 17% 4% 15 mi 5.3°F ? 4 mph 83%
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
0% Total
Low
0%
Mid
0%
High
0%
8 PM
0% Total
Low
0%
Mid
0%
High
0%
9 PM
0% Total
Low
0%
Mid
0%
High
0%
10 PM
0% Total
Low
0%
Mid
0%
High
0%
11 PM
1% Total
Low
0%
Mid
0%
High
1%
12 AM
2% Total
Low
0%
Mid
0%
High
2%
1 AM
2% Total
Low
0%
Mid
0%
High
2%
2 AM
0% Total
Low
0%
Mid
0%
High
0%
3 AM
0% Total
Low
0%
Mid
0%
High
0%
4 AM
0% Total
Low
0%
Mid
0%
High
0%
5 AM
7% Total
Low
0%
Mid
0%
High
7%
6 AM
17% Total
Low
0%
Mid
0%
High
17%
Why this score?

Limiting Factors

Humidity 75% High impact
Visibility 15 mi Moderate impact
Dew Spread 8.5°F Moderate impact
Wind 5 mph Low impact
High Clouds 2% Low impact
Source Comparison

Forecast Sources

MVP starts with Open-Meteo; additional sources will improve confidence scoring.
Source Clouds Rain Humidity Wind Status
Open-Meteo 2% 5% 75% 5 mph Primary forecast
Tomorrow.io -- -- -- -- Secondary forecast active
National Weather Service -- -- -- -- No severe alert cap