Daylight hours in Rockford
Rockford gets 15h 15m of daylight on its longest day in June, and 9h 06m on its shortest in December — a difference of 6h 09m across the year.
How fast the days change
Around 17 March, Rockford gains or loses about 2.9 minutes of daylight every day.
Enough to notice over a fortnight, though the seasons arrive more gently here than further from the equator.
Sunrise and sunset by month
On the 15th of each month, in America/Chicago local time, daylight saving included.
| Month | Sunrise | Sunset | Daylight | Solar noon |
|---|---|---|---|---|
| January | 07:22 | 16:49 | 9h 27m | 12:05 |
| February | 06:52 | 17:28 | 10h 36m | 12:10 |
| March | 07:07 | 19:02 | 11h 55m | 13:05 |
| April | 06:15 | 19:37 | 13h 23m | 12:56 |
| May | 05:34 | 20:10 | 14h 36m | 12:52 |
| June | 05:19 | 20:34 | 15h 15m | 12:56 |
| July | 05:33 | 20:31 | 14h 58m | 13:02 |
| August | 06:04 | 19:57 | 13h 53m | 13:00 |
| September | 06:36 | 19:06 | 12h 30m | 12:51 |
| October | 07:09 | 18:14 | 11h 05m | 12:42 |
| November | 06:47 | 16:34 | 9h 47m | 11:40 |
| December | 07:18 | 16:24 | 9h 06m | 11:51 |
Solstices and equinoxes
| Date | Sunrise | Sunset | Daylight | |
|---|---|---|---|---|
| March equinox | 20 Mar | 06:59 | 19:08 | 12h 09m |
| June solstice | 21 Jun | 05:20 | 20:36 | 15h 16m |
| September equinox | 22 Sep | 06:44 | 18:53 | 12h 10m |
| December solstice | 21 Dec | 07:22 | 16:27 | 9h 05m |
The equinoxes give almost exactly twelve hours of daylight everywhere on earth — "almost" because sunrise is defined by the sun's upper edge rather than its centre, and the atmosphere bends its light over the horizon before it has really arrived. Both lengthen the day by a few minutes.
Other cities in United States
Assumptions
- Sea-level horizon. Hills, mountains and buildings all delay sunrise and bring sunset forward, sometimes by a lot in a valley.
- Standard refraction. Sunrise is taken at −0.833°, allowing for the sun's disc and average atmospheric bending. Unusual air conditions shift it by a minute or two.
- Local clock time, with daylight saving applied from the IANA timezone database.