To estimate how long until sunset using your fingers, you can try these steps:
- Find a clear view of the sun and horizon
- Extend your arm and fingers towards the sun
- Bend your wrist so your palm faces you
- Align the top of your outstretched hand with the bottom of the sun
- Count how many fingers it takes to reach the top of the horizon line
Each finger represents about 15 minutes of daylight remaining. If you need to estimate a time more than an hour away, you can stack one hand on top of the other and continue counting. For example, if you count three hands, there are three hours until sunset.
This technique works best if the horizon is flat or a mountain ridge line, but the accuracy may vary depending on your latitude. For example, in the Pacific Northwest, you can add about 30 minutes to the sunset time to account for total darkness. You should also keep in mind that the Earth’s atmosphere refracts sunlight as the sun approaches the horizon, so you may actually have more daylight than you think. This is known as civil twilight, and it can last for at least 24 minutes after the sun has dropped more than 6 degrees below the horizon.