Finding good weather and meteorological application focused and useful for astronomy can be a challenge as resources are numerous and provide a varying degree of data. Moreover, many sites provide the same data in a different format and do not add anything of value to the astronomer, but personal preference for how to view the data. Therefore, we have reviewed and provided our favorite meteorologically related astronomy websites for your use. We provide a score and a little bit of personal experience to each review as well.
Some of the areas to consider:
- Who owns and maintains the site?
- What data is provided?
- How often is the website updated?
- Ease of use
- Does the website have a smartphone app?
ClearOutside is a website run by UK company First Light Optics Ltd and is a weather forecasting site for astronomers. The design of ClearOutSide is the sleekest of these sites and easiest to use and learn. The colors are easy to understand and intuitive, but the data is very similar in depth. The best way to explain ClearOutside would be to combine the Meteoblue and Wunderground data and make the site easy to interact with. The site is updated hourly and provides a 7 day forecast, including ISS flyovers and the ability to center the chart on the current hour or midday. Some areas for improvement would be the inclusion of what planets and celestial objects are available; however, this site is really intuitive and easy to use. There is an available iOS App on the Apple Store.
ClearDarkSky has charts that are “based on a numerical weather model,” providing “forecasts of astronomical observing conditions for over 1900 observatories and observing sites in North America.” The site is written and maintained by Attila Danko, which is based on the forecasting model developed by Allan Rahill of the Canadian Meteorological Center. The charts for the 1900 observatories that are in the Cleardarksky database, provides astronomy forecasting at a glance for 48 hour periods for the clearness and darkness of the sky for a specific site.
This is intended for amateur astronomers and is updated 2 times a day, typically at 9am and 9pm PST. There is a mobile app available for iOS and Android, which keeps the same format of the website. This site is easy to look at, but is hard to understand, as there is data for the Cloud Cover, Transparency, Seeing, Darkness, Wind, Humidity, and Temperature. The seeing is adjusted for an 8 inch scope, so the data will vary depending on scope size.
It takes time to learn the site and what the colors are, which are not totally intuitive. This site is a great resource to use as a quick guide or a secondary resource, as it lacks the real time functionality that some of the other sites function. Another issue is that the available locations are limited and predetermined, so if one is going to an area that is not already entered into the database, ClearDarkSky is only a best guess. A positive of the site is that it includes the light pollution level and explanations of each level when looking at the chart overview for each state of territory.
Wunderground.com is a weather site owned by The Weather Channel (which is an IBM subsidiary), providing real time meteorological data for cities around the world. This site does not provide this data targeted towards astronomers, but is an accurate and up to date weather site. Items such as cloud cover, precipitation percent, visibility, and humidity is all broken down on an hourly basis for up to 10 days. The negative is that other than cities, there is limited weather data related to specific astronomy sites that are not near cities. But the positives are the accurate and up to date data, which are really helpful for planning what to wear and bring for astronomy.
Founded in 2006, meteoblue offers forecasting models based on NOAA/NCEP data. Meteoblue provides a wide range of services to users from forecasts, meteograms, and Astronomical Seeing.
The focus for amateur astronomers is the meteoblue Astronomical Seeing, which has a forecast for 3 days and is typically updated twice daily. There is an opportunity to subscribe for extended 7 day forecast for a fee of $57.50, which would provide additional features as well. The Astronomical Seeing forecast provides the same data as ClearDarkSky, except for the wind speed, but also provides additional data and features that ClearDarkSky lacks. Meteoblue adds data about the rise and set celestial bodies (planets), the rise and set times for sun and moon, more detailed atmospheric and seeing information, and is broken down by hour. This allows for an easier learning experience and an easier platform to understand.
This site is great and a great place to start a search. A huge positive of using meteoblue is the granularity and depth in terms of choosing a location to forecast. It is definitely more in depth than the other sites on this list. The only negative is that the site is updated 2 times a day and only provides a 3 day forecast by default. This is a great primary source!
Always check the weather when heading out to do astronomy of any type, which is why we included a weather site like wunderground. In terms of primary sites, it is recommended to start at either ClearOutside or Meteoblue and use ClearDarkSky if one is using a telescope or binoculars. Doing wide field DSLR imaging or naked eye viewing doesn’t require the data provided by ClearDarkSky. ClearDarkSky is great, but the weather will change between the time that ClearDarkSky was updated and the current conditions.