If you run the "date" command in Linux, it will output the system time:
pi@raspberrypi ~ $ date
Sat Nov 28 08:28:56 PST 2015
In HG, the log file will display a time stamp for all actions which should match your Linux time:
2015-11-28 08:30:06.2102 Info WebServiceGateway 192.168.0.5 HTTP GET 200 /hg/html/pages/control/widgets/jkUtils/SolarAltitude/images/Widget.Preferences.png [OPEN]
Beyond that, you need to have the weather APP that provides the sunrise/sunset set to the correct location. jkUtils utilizes a lat/long while WU and OpenWeatherMap use a city.