There are several ways to see cloud tops information.
Via a Graphical Briefing
The ForeFlight graphical weather briefing includes the Cloud Coverage graphic. This image displays cloud bases and tops along with any icing and mountain obscuration AIRMETs. The Cloud Coverage graphic can be found by retrieving a briefing on the Flights page. Navigate to the Forecasts section > Cloud Coverage.
Image 1. Cloud coverage chart in a graphical briefing with tops shown.
PIREPs provide another source of cloud tops.
Image 2. PIREPs often have cloud top reports.
You can also infer actual tops by going to the Imagery tab in ForeFlight and selecting Infrared. These static IR satellite images provide you with cloud top temperature. Basically, the colder the cloud top, the higher the clouds. While there are important limitations, simply find the height of that temperature shown on the static IR image using our winds and temperatures aloft section in the Winds Aloft tab while looking at airport weather. You can also use the winds that are generated during a briefing.
Image 3. Use the IR satellite images to find the temperature at cloud top.
Image 4. Use the Winds Aloft information to find the altitude of the temperature.
Via Cloud Tops Layer
In flight, if ForeFlight is receiving XM or ADS-B weather through an external receiver, a Cloud Tops layer will be available on the Maps page.
Image 5. Cloud tops via XM.