Astronomy Tools
South African observing forecast
Clear Sky Indicator
Find the most promising observing window by comparing cloud cover, humidity, dew risk, wind and rain over the next seven nights.
Observing location
Choose a town, use your current position, or enter coordinates.
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Observing mode
The rating adjusts to the activity you select.
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Checking cloud, humidity, wind and rain conditions.
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Tonight
Cape Town observing outlook
Calculating the best observing window…
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Seven-night outlook
Select a night to see its detailed observing conditions.
Night details
Hourly forecast for the selected night.
Forecast intervals become broader later in the outlook as the weather model changes from short range to medium range.
How the observing score works
The score is a practical guide, not a guarantee of local conditions.
Cloud cover
The largest part of the score. Low, medium and high cloud layers are shown separately.
Dew risk
A small gap between temperature and dew point increases the chance of condensation on optics.
Wind
Strong wind affects telescope stability and is penalised more heavily for imaging and planetary work.
Rain and fog
Forecast precipitation or fog sharply reduces the observing rating.
Weather data from the Norwegian Meteorological Institute (MET Norway), licensed under CC BY 4.0. AstroClassifieds converts the data into an observing score. The score does not directly predict atmospheric seeing or light pollution. Forecasts are automated global model guidance and may not capture local cloud, mist or mountain conditions.