| Geyser | 1999-12-01 |
|---|---|
| Grand | 0447 E, 1529 E |
| Great Fountain | 1624 E |
| Values for Old Faithful Area | 1999-12-01 |
|---|---|
| Astronomical Twilight Begin | 05:55 |
| Nautical Twilight Begin | 06:30 |
| Civil Twilight Begin | 07:06 |
| Sunrise | 07:39 |
| Sunset | 16:45 |
| Civil Twilight End | 17:17 |
| Nautical Twilight End | 17:54 |
| Astronomical Twilight End | 18:29 |
| Moon Illumination | 36.47% |