Autumnal Equinox to occur on September 23 — PAGASA

State weather bureau PAGASA says an Autumnal Equinox will occur Friday next week, September 23. It means the night and day will have equal length on Earth.

But, a website that provides information time and date related, has dispelled the “exactly 12 hours of daylight” myth.

In its website, explained why an equinox does not have exactly 12 hours of daylight.

During the equinox, according to, “the length of night and day across the world is nearly, but not entirely, equal” because “the day is slightly longer in places that are further away from the equator, and because the sun takes longer to rise and set in these locations.”

Furthermore, “the sun takes longer to rise and set farther from the equator because it does not set straight down - it moves in a horizontal direction,” the site said. Click here for a more detailed explanation.

The September equinox occurs at 9:04 a.m. Coordinated Universal Time (UTC) on September 23, 2011. The next September equinoxes will take place on the 21st of the month in the year 2092 and on the 24th in the year 2303.

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