Daylight hours in Heihe
Heihe gets 16h 23m of daylight on its longest day in June, and 8h 04m on its shortest in December — a difference of 8h 19m across the year.
How fast the days change
Around 17 March, Heihe gains or loses about 3.8 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 Asia/Shanghai local time, daylight saving included.
| Month | Sunrise | Sunset | Daylight | Solar noon |
|---|---|---|---|---|
| January | 07:23 | 15:54 | 8h 31m | 11:39 |
| February | 06:41 | 16:46 | 10h 05m | 11:44 |
| March | 05:44 | 17:33 | 11h 50m | 11:39 |
| April | 04:37 | 18:23 | 13h 46m | 11:30 |
| May | 03:43 | 19:09 | 15h 26m | 11:26 |
| June | 03:19 | 19:41 | 16h 23m | 11:30 |
| July | 03:36 | 19:35 | 15h 59m | 11:36 |
| August | 04:18 | 18:50 | 14h 31m | 11:34 |
| September | 05:05 | 17:45 | 12h 40m | 11:25 |
| October | 05:51 | 16:39 | 10h 48m | 11:15 |
| November | 06:43 | 15:45 | 9h 03m | 11:14 |
| December | 07:22 | 15:27 | 8h 04m | 11:25 |
Solstices and equinoxes
| Date | Sunrise | Sunset | Daylight | |
|---|---|---|---|---|
| March equinox | 20 Mar | 05:33 | 17:41 | 12h 09m |
| June solstice | 21 Jun | 03:19 | 19:44 | 16h 25m |
| September equinox | 22 Sep | 05:16 | 17:29 | 12h 14m |
| December solstice | 21 Dec | 07:26 | 15:28 | 8h 02m |
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 China
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.