How Cool was the Eclipse?

The Earth is solar-powered. So what happens when the Sun's light is blocked, even temporarily? If you measure air and surface temperature, how cool is an eclipse?

More than 10,000 observers helped us collect more than 20,000 cloud observations with 60,000 photos and 80,000 air temperature measurements to answer these questions and others using the GLOBE Observer app during the Total Solar Eclipse on August 21st, 2017.

These citizen scientists were able to:

  • Observe how the eclipse changes atmospheric conditions near you
  • Contribute to a citizen science database used by scientists and students to study the effects of eclipses on the atmosphere
  • Provide comparison data even if they were not in the path of totality

GLOBE Observer eclipse app button

The eclipse app button is no longer available in the GLOBE Observer app, but you can still make clouds observations any time, and watch for the eclipse features to be back during the next eclipse. In the meantime, visit our Eclipse Data Analysis page to see more about the analysis of the data, including how you can download it to explore your own questions.

Need to get the app? Learn how here.

Other questions that aren't answered below? Try the eclipse FAQs page.

Looking for printable GLOBE Observer materials and other activities? Visit the eclipse resources or clouds resources pages.

Want a quick look at the air temperature data coming in? Take a look at the eclipse data visualization page. (An animation of the data is viewable below)

How should I make observations during the eclipse?

First and foremost, make sure you are being safe when you are observing the eclipse. Looking directly at the Sun is unsafe except during the brief total phase of a solar eclipse (“totality”), when the moon entirely blocks the Sun’s bright face, which will happen only within the narrow path of totality. For more details about how to observe safely, including the appropriate type of eclipse glasses and filters to use, visit the NASA Eclipse 2017 webpage.

Also, a total solar eclipse is an amazing experience, apart from the interesting science involved. Especially for first-time eclipse observers, we recommend you put down your phone or camera during the precious few minutes of totality itself and just enjoy the experience. The data collection procedures below take that into account, and ask you to make observations and measurements before and after totality, but not during totality itself.

Cloud Type and Cover

Three people observing the clouds.

The simplest way to participate without needing any additional equipment is by making clouds observations using the GLOBE Observer app. Clouds are an important part of the Earth's energy budget, and you may observe changes as the Sun becomes more and more blocked during the eclipse. We would like you to make regular observations for about two hours before and after the point of maximum eclipse. That will cover the period when the moon first starts blocking the Sun, called first contact, all the way to last contact, when the moon moves completely past the Sun and is no longer blocking any portion of it.

Try to make observations about every 15-30 minutes, more often if you wish, especially any time you notice something changing. If you are also measuring air temperature, the special eclipse page on the app will remind you with notifications to make your measurements about every third air temperature measurement. Feel free to add narrative comments to your photos about anything interesting you see happening.

Air Temperature

Hand holding thermometer

If you'd like to take it a step further and get a separate thermometer (anything from a simple liquid-filled thermometer to more complex digital models - see more about different types here), you can also collect and report data about air temperature on a special page that will be available in the GLOBE Observer app starting on August 18th. Whatever type of thermometer you use, make sure you are taking your measurements in the shade, even if that is just the shadow of your body with the thermometer held at arm's length.

Here's the preferred schedule for air temperature measurements:

  • For two hours before and after maximum eclipse, take a measurement every ten minutes.
  • If you can, increase that to every five minutes for the half hour before and after totality or the maximum eclipse at your location.
  • You can also take measurements the day before the eclipse. Ideally, these would be near the time maximum eclipse will occur the following day. For example, if the time of totality for your location is 10:15 am on August 21st, make measurements at about 10:15 on August 20th.

Surface Temperature and Other Variables

There are many other atmospheric variables that could be interesting to observe, but won't have a designated place to enter via the GLOBE Observer app. For example, surface temperature using an infrared thermometer or wind speed and direction using an anemometer (wind speed gauge). These types of observations can always be noted in the comments of a cloud or air temperature measurement. For those willing to put in a bit of extra time to be trained in the GLOBE surface temperature protocol, acquire an infrared thermometer and set up an observation site, you can collect that data during the eclipse and report it through the GLOBE Data Entry app or via the online data entry form. You can find more information about the training requirements on the protocol eTraining page. To measure surface temperature, you will need to complete an introduction to GLOBE, an introduction to the atmosphere protocols generally, and then learn how to do the surface temperature protocol specifically. The training slides can be downloaded by anyone, but you will need to log in with your GLOBE Observer account information to take the short quizzes to get credit for the training and be able to enter data. Especially for educators, you may find the eclipse page on the GLOBE formal education website useful.

More Information and Other Citizen Science Projects During the Eclipse

For general information about eclipses, as well as maps of planned events, video interviews with scientists, and much more, visit the NASA Eclipse 2017 website. They also have suggestions about how to observe the dimming of daylight, and other activities you can try before or after the eclipse. For those with telescopes and especially those on the path of totality, another project looking for volunteers is the Citizen Continental-America Telescopic Eclipse Experiment, or Citizen CATE. Apps such as iNaturalist or iSeeChange are also venues for reporting general observations of nature, during the eclipse or any time.