Riverton, WY: shortest day and earliest sunset
The shortest day in Riverton
On Dec 21 the sun rises at 7:42 am and sets at 4:42 pm: 9h 00m of daylight, a moderate winter. The longest day of summer has 15h 22m, so the swing is 6h 22m.
When it gets better in Riverton
- Earliest sunset: 4:39 pm on Dec 9, before the shortest day (here is why).
- Latest sunrise (standard time): 7:45 am on Jan 2.
- Back above 10 hours of daylight: Feb 3.
- By Feb 21 the days grow by 2.8 minutes a day.
Waking and coming home in the dark
With a 7:00 am alarm, the sun is not yet up on 114 weekdays a year. Heading home at 5:30 pm, it has already set on 68. 61 weekdays start and end in the dark. The alarm and lamp guide shows how that compares across the country.
At 43.0°N this is as far north as, or farther than, Nashua NH (43°N), where a 1990 survey found 9.7% of adults reported winter depression.
What to do about it in Riverton
- A sunrise alarm clock is worth getting here: on 72 weekdays the sun is still at least 20 minutes from rising at 7:00 am. Dark mornings run from Sep 22 to Mar 29, so set it up before Sep 22.
- On daylight grounds there is a strong case for a light therapy lamp: 61 weekdays start and end in the dark. Use it in the morning, and if winter low mood is the reason, ask a doctor before you rely on one.
- If you head home at 5:30 pm, the sun has already set from Nov 2 to Feb 3: worth checking your bike lights and porch light before Nov 2.
Daylight in Riverton, month by month
Sunrise, sunset and day length on the 21st of each month, local clock time. December is the darkest, at 9h 00m.
| Month | Sunrise | Sunset | Daylight |
|---|---|---|---|
| July 2026 | 5:53 am | 8:46 pm | 14h 52m |
| August 2026 | 6:26 am | 8:06 pm | 13h 40m |
| September 2026 | 7:00 am | 7:12 pm | 12h 12m |
| October 2026 | 7:35 am | 6:21 pm | 10h 46m |
| November 2026 | 7:14 am | 4:45 pm | 9h 31m |
| December 2026 | 7:42 am | 4:42 pm | 9h 00m |
| January 2027 | 7:38 am | 5:12 pm | 9h 33m |
| February 2027 | 7:02 am | 5:53 pm | 10h 50m |
| March 2027 | 7:15 am | 7:27 pm | 12h 12m |
| April 2027 | 6:22 am | 8:03 pm | 13h 41m |
| May 2027 | 5:45 am | 8:36 pm | 14h 52m |
| June 2027 | 5:34 am | 8:56 pm | 15h 22m |
Riverton against the places around it
On the shortest day, compared with Riverton (9h 00m, sunset 4:42 pm):
- Casper, WY, 105 mi away: 9h 01m of daylight (+1 min), sunset 4:34 pm (-8 min).
- Rock Springs, WY, 108 mi away: 9h 10m of daylight (+10 min), sunset 4:50 pm (+8 min).
- Cody, WY, 109 mi away: 8h 49m of daylight (-11 min), sunset 4:39 pm (-3 min).
- Green River, WY, 118 mi away: 9h 10m of daylight (+10 min), sunset 4:51 pm (+9 min).
- Jackson, WY, 124 mi away: 8h 57m of daylight (-3 min), sunset 4:50 pm (+8 min).