The main function of Sun Times is to display day and night moving across a map of the world's time zones. It calculates and tabulates sunrise, sunset, dawn and dusk times for over 10,000 locations covering the world's land surface. It also displays the current local time in each of these locations with daylight saving adjustments. In addition, it calculates the times of events which are based on the local position of the sun, eg Islamic prayer times.

In addition to this main Sun Times function it has climate, aviation, geographical and astronomical features. The climate features display expected seasonal temperatures and precipitation, estimates of current temperatures based on the local time of day, tables of in depth climate data, and illustration of departures from long-term climate averages (for year 2000 onwards). The aviation features allow some of the scheduled worldwide commercial flights to be plotted and animated, airline route networks to be illustrated and tabulated, timetabled departure and arrival boards to be generated, and idealised airspace capacity demands to be plotted.

A further aviation feature allows you to investigate how flying across the world's time zones will affect the observed time of sunrise and sunset. The geographical features tabulate the time zone, daylight savings rule, region and population of locations in Sun Times, and show populations (for 2007) for cities, regions and countries. The astronomical features allow the movement of the Sun, Moon and naked-eye planets to be plotted relative to each other or relative to an observer's horizon.