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UK Extremes

High Temp
14.1° C
Bridlington Mrsc
Low Temp
-4.3° C
Cairngorm
Precipitation
11.4 mm
Fair Isle
Wind Gust
46.0 mph
Camborne

Astronomy Forecast for Southampton

Cloud cover, astronomical seeing and atmospheric transparency for the next three days - the conditions that actually decide whether tonight's a good night to get the telescope out.

Forecast run issued 2026-11-10 06:00 UTC • Cached 13:11

Key: ■ Good/Clear   ■ Average/Partly Cloudy   ■ Poor/Cloudy   •   rows shaded blue are evening/overnight hours (20:00-07:00 local).

Tuesday 10 November

Time Cloud Cover Seeing Transparency Stability Wind Temp Precip
09:00 94-100% (Cloudy) 1-1.25" (Average) 0.5-0.6 (Average) Stable E Moderate 6°C None
12:00 94-100% (Cloudy) 1.25-1.5" (Average) 0.5-0.6 (Average) Stable E Moderate 7°C Rain
15:00 94-100% (Cloudy) 1-1.25" (Average) 0.7-0.85 (Poor) Stable E Moderate 6°C Rain
18:00 94-100% (Cloudy) 1-1.25" (Average) >1 (Poor) Stable E Moderate 6°C Rain
21:00 94-100% (Cloudy) 1-1.25" (Average) >1 (Poor) Stable NE Moderate 6°C Rain

Wednesday 11 November

Time Cloud Cover Seeing Transparency Stability Wind Temp Precip
00:00 94-100% (Cloudy) 1.25-1.5" (Average) >1 (Poor) Stable NE Moderate 7°C Rain
03:00 94-100% (Cloudy) 1.25-1.5" (Average) >1 (Poor) Stable NE Moderate 7°C Rain
06:00 94-100% (Cloudy) 1-1.25" (Average) >1 (Poor) Stable NE Moderate 7°C Rain
09:00 94-100% (Cloudy) 1-1.25" (Average) >1 (Poor) Stable NE Moderate 7°C Rain
12:00 94-100% (Cloudy) 1-1.25" (Average) >1 (Poor) Stable NE Moderate 7°C Rain
15:00 94-100% (Cloudy) 1-1.25" (Average) >1 (Poor) Stable NE Moderate 7°C Rain
18:00 94-100% (Cloudy) 1.25-1.5" (Average) 0.85-1 (Poor) Stable NE Moderate 7°C Rain
21:00 94-100% (Cloudy) 1.25-1.5" (Average) 0.6-0.7 (Average) Stable NE Moderate 7°C None

Thursday 12 November

Time Cloud Cover Seeing Transparency Stability Wind Temp Precip
00:00 94-100% (Cloudy) 1.25-1.5" (Average) 0.7-0.85 (Poor) Stable NE Moderate 6°C None
03:00 6-19% (Clear) 1.5-2" (Poor) 0.5-0.6 (Average) Stable NE Moderate 4°C None
06:00 6-19% (Clear) 1.5-2" (Poor) 0.6-0.7 (Average) Stable NE Moderate 3°C None
09:00 6-19% (Clear) 1-1.25" (Average) 0.5-0.6 (Average) Stable NE Moderate 4°C None
12:00 6-19% (Clear) 1-1.25" (Average) 0.5-0.6 (Average) Stable NE Moderate 6°C None
15:00 31-44% (Partly Cloudy) 1.25-1.5" (Average) 0.3-0.4 (Good) Stable NE Moderate 5°C None
18:00 19-31% (Clear) 1.5-2" (Poor) 0.4-0.5 (Good) Stable N Moderate 2°C None
21:00 0-6% (Clear) 1.5-2" (Poor) 0.4-0.5 (Good) Stable N Moderate 1°C None

Friday 13 November

Time Cloud Cover Seeing Transparency Stability Wind Temp Precip
00:00 0-6% (Clear) 1.5-2" (Poor) 0.4-0.5 (Good) Stable N Light 0°C None
03:00 0-6% (Clear) 2-2.5" (Poor) 0.4-0.5 (Good) Stable N Light -1°C None
06:00 0-6% (Clear) 2-2.5" (Poor) 0.4-0.5 (Good) Stable N Light -1°C None

Reading It

Cloud cover is the obvious one - no point setting up if it's a solid grey sky. But two clear nights can still look very different through a telescope, which is where the other two columns matter:

Astronomical seeing measures how steady the air is, in arcseconds - turbulence in the atmosphere is what makes stars twinkle and blurs fine detail on planets and the Moon, even under a perfectly clear sky. Smaller numbers are better (under 1" is good, over 2" means the image will visibly shimmer).

Atmospheric transparency measures how much starlight is lost to haze, thin high cloud or dust that isn't necessarily obvious to the naked eye - given in magnitudes lost per air mass. Smaller numbers mean a clearer, darker sky, which matters most for faint targets like galaxies and nebulae rather than bright ones like the Moon or planets.

Stability (the atmosphere's "lifted index") flags a raised risk of thunderstorms or sudden cloud building when marked Unstable, regardless of what the cloud forecast says right now.

See also: Sun, Earth & Moon • Night Sky Viewer • Sun Position • Meteor Shower Calendar

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