ClearDarkSky.com, created by Attilla Danko, provides an astronomer’s forecast. It shows at a glance when, in the next 96 hours, you might expect clear and dark skies for a specific observing site. The data comes from a forecast model developed by Allan Rahill of the Canadian Meteorological Center. The clear sky chart predicts hourly cloud cover, atmospheric transparency, and seeing conditions, which are crucial for planning whether to observe galaxies or planets.

ClearDarkSky.com also offers a light pollution map to help you find the best observing locations. If you find these forecasts useful, consider emailing Allan Rahill to support his work and show that his astronomy forecasts are being used. For more frequent updates and additional features, consider sponsoring a chart.