On your Garmin the out of the box Sunrise and Sunset widget displays civil twilight times... https://www8.garmin.com/manuals/webhelp/fenix66s6xpro/EN-US/GUID-

On your Garmin the out of the box Sunrise and Sunset widget displays civil twilight times... https://www8.garmin.com/manuals/webhelp/fenix66s6xpro/EN-US/GUID-97EA1540-A780-480F-BA4D-9A9E147FB225.html https://www8.garmin.com/manuals/webhelp/fenix66s6xpro/EN-US/... Or check the Solaris watch face which shows civil twilight, nautical twilight, astronomical twilight, and night. https://apps.garmin.com/en-US/apps/0e019a96-aeb3-4aaf-81ed-4c096b8aca2a https://apps.garmin.com/en-US/apps/0e019a96-aeb3-4aaf-81ed-4... Above subject to which device you have.