Over the course of January, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 1:05 hours, implying an average day-over-day increase of 2.1 minutes.
The shortest day of the month is January 1 with 8:15 hours of daylight; the longest day is January 31 with 9:20 hours of daylight.
Daily Hours of Daylight and Twilight in January
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 6Â° from the horizon), civil twilight (Sun is not visible but is less than 6Â° below the horizon), nautical twilight (Sun is between 6Â° and 12Â° below the horizon), astronomical twilight (Sun is between 12Â° and 18Â° below the horizon), and full night.
The earliest sunrise is at 7:51am on January 31; the latest sunset is at 5:11pm on January 31; the latest sunrise is at 8:13am on January 1; the earliest sunset is at 4:28pm on January 1.
Daylight saving time is observed in 2012 but it neither starts nor ends in January, so the entire month is in standard time.
Daily Sunrise & Sunset with Twilight and Daylight Saving Time in January
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.