Daylight hours in Thunder Bay
Thunder Bay gets 16h 05m of daylight on its longest day in June, and 8h 21m on its shortest in December — a difference of 7h 44m across the year.
How fast the days change
Around 17 March, Thunder Bay gains or loses about 3.6 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/Toronto local time, daylight saving included.
| Month | Sunrise | Sunset | Daylight | Solar noon |
|---|---|---|---|---|
| January | 08:43 | 17:29 | 8h 47m | 13:06 |
| February | 08:03 | 18:18 | 10h 15m | 13:11 |
| March | 08:09 | 20:02 | 11h 52m | 14:05 |
| April | 07:06 | 20:47 | 13h 41m | 13:56 |
| May | 06:16 | 21:30 | 15h 14m | 13:53 |
| June | 05:55 | 22:00 | 16h 05m | 13:57 |
| July | 06:12 | 21:54 | 15h 42m | 14:03 |
| August | 06:51 | 21:11 | 14h 20m | 14:01 |
| September | 07:34 | 20:10 | 12h 36m | 13:52 |
| October | 08:17 | 19:08 | 10h 51m | 13:42 |
| November | 08:04 | 17:18 | 9h 13m | 12:41 |
| December | 08:41 | 17:02 | 8h 21m | 12:52 |
Solstices and equinoxes
| Date | Sunrise | Sunset | Daylight | |
|---|---|---|---|---|
| March equinox | 20 Mar | 07:59 | 20:09 | 12h 10m |
| June solstice | 21 Jun | 05:55 | 22:02 | 16h 06m |
| September equinox | 22 Sep | 07:44 | 19:55 | 12h 11m |
| December solstice | 21 Dec | 08:45 | 17:04 | 8h 19m |
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 Canada
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.