Over the course of September, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1:33 hours, implying an average day-over-day decrease of 3.1 minutes.
The shortest day of the month is September 30 with 11:44 hours of daylight; the longest day is September 1 with 13:17 hours of daylight.
Daily Hours of Daylight and Twilight in September
The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.
The earliest sunrise is at 6:21am on September 1; the latest sunset is at 7:38pm on September 1; the latest sunrise is at 6:58am on September 30; the earliest sunset is at 6:41pm on September 30.
Daylight saving time is observed in 2012 but it neither starts nor ends in September, so the entire month is in daylight time.
Daily Sunrise & Sunset with Twilight and Daylight Saving Time in September
The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the "DST" labels.
Ally Garber
Timsplosion