No, this isn't referring to the chorus of an oldies tune.

Specifically, several users have commented on the time of sunrise and/or sunset in certain templates being unrealistic. Until now I had no idea what to do about it.

Sunrise and sunset times are specific to a route, not to a template, and can be modified using Route-Riter. Select the route in question, then go to the "Misc. Options" tab. When this opens, under the "Environment" section first click on "Set Up New Env Files". Finally, click on "Correct Sun Rise/Set". R-R automatically backs up the env files, so if it doesn't work out, you can always back track.

The basic routes have only one sunrise and one sunset time for all seasons. R-R figures corrected values based on latitude and longitude for all four seasons, and even takes into account the use of daylight savings time!

Even though sunrise and sunset is not actually determined by the activity template, the activity need not start in the dark. The default starting time is set up when the template activity file is created, and does not change with the season. But the activity starting time can be modified when AG is used to generate the activity, or via AM.