A diverse society and economy requires balanced time planning.

The graph below shows daylight, by day of the year, centered on mid-day. The values are here: Details (see also: end notes).

• Calculations are centered at Tan Son Nhat International Airport (10.8155354°, 106.6640496°, UTC+07:00)
• There is no Daylight Savings Time in Vietnam, as is common so close to the equator.
• Civil Twilight begins (and ends) when the Sun is 6° below the horizon. By this time, little artificial light is necessary for outdoor activities, depending, as always on the weather. Civil Twilight is always earlier than the apparent sunrise based upon Atmospheric Refraction (light bends!). Apparent Sunrise is a scientific standard useful for precise measurements of climate, but inappropriate for social and economic planning. For example, in Ho Chi Minh City, the average Solar Noon (the Sun at highest point in the sky), year-round, in 2011 occurs at 11:53 AM. Family Time revolves around this "Noon", and your economic role as both a producer and consumer does too.