Starting on the Equinox
Starting on the fall equinox (September 22), report your daylight length each month throughout the coming year.
Photo: Sergio Locatelli
How to Participate
Report on the 20th of every month, and on each equinox and solstice. Track changes in daylight over the course of the year on the daylight map. Explore how day length changes in your part of the world as the Earth revolves around the Sun. Share and compare seasonal observations with people around the globe.
What to Report
How to Report your Day Length (Photoperiod)
Step 1: Look up your sunrise/sunset on the 20th of every month.
Step 2: Calculate the length of time between sunrise and sunset.
Step 3: Report your daylight length on the 20th of every month.
Step 4: Explore the daylight map and compare your part of the world with other locations as the Earth revolves around the Sun.