The best weather for stargazing

Many believe astronomy is the oldest science in human history. Historically, it was a reason to go outside when the weather is right, and look to the heavens in search of inspiration or inner peace.

Technology now allows modern astronomers to stargaze with greater clarity. However, technology has not changed the important connection between astronomy and weather conditions.

Here are a number of factors to consider when deciding if tonight is the night to look out at the stars.

The best weather for stargazing

It’s very frustrating to set up a telescope and look to the sky only to see clouds.. A cloudless sky is of the utmost importance to enjoy astronomy. There are several great websites for budding and experienced astronomers. One site, Clear Dark Sky, uses data from more than 1,900 observatories and North American observing sites to specifically forecast ideal conditions for astronomy.

Cloud cover isn’t the only weather-related condition that matters to astronomy. Transparency and Seeing are also crucial, but these terms probably aren’t as familiar to most people.

Transparency: Transparent conditions refer to the clarity in the sky. If there is no humidity or dust, then the transparency is good. Transparency is typically best in the winter and poor in the summer.

Seeing: Seeing conditions refer to the stability of the atmosphere. If you’ve ever thought the stars look like they are “dancing,” that’s a sign of poor seeing. With poor seeing conditions, celestial objects appear to shimmer. Details will be blurry, which is unfavorable to a satisfying night of stargazing. Seeing is always better late at night and worse in early evening. 

Forecasting the best weather conditions for astronomy

When it comes to astronomy, it’s risky to make plans based on what you might hear during the nightly TV weather report. Those “clear sky” forecasts are usually geared to help people decide if it’s going to rain more than they are meant to be a tool to plan an astronomy outing.

Weather websites like AccuWeather or sites devoted to the science of astronomy have more accurate and useful data, with relevant information for your local area including cloud forecasts, wind speed, pressure and temperature. These sites also offer convenient graphics, charts and satellite images that are useful for understanding the cloud cover conditions later in the evening. Infrared, or thermal, images are also very useful to determine the different temperatures that can affect your stargazing .

Barometric pressure charts will help you forecast clarity. (High pressure signifies clearer conditions and low pressure warns of unfavorable conditions for satisfying astronomy.)

If you find yourself becoming serious about astronomy, consider investing in a home weather station. This tool will tell you the current pressure, wind speed, and direction. (Low wind speed is associated with good seeing conditions.)

Astronomy is a fascinating science, a stimulating hobby and a fun experience to share with your family. But a telescope isn’t all you will need to stargaze. To really get the most out of an astronomy outing, and to avoid the frustrating complaint that there’s “nothing to see,” it helps to make use of the various websites and tools that specialize in forecasting conditions for astronomy before you go outside.

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