| Geyser | 1999-12-19 |
|---|---|
| Grand | 0914 E, 1917 E |
| Great Fountain | 0330 E, 1435 E |
| Hillside-West Thumb | 0957 |
| Values for Old Faithful Area | 1999-12-19 |
|---|---|
| Astronomical Twilight Begin | 06:09 |
| Nautical Twilight Begin | 06:45 |
| Civil Twilight Begin | 07:21 |
| Sunrise | 07:55 |
| Sunset | 16:45 |
| Civil Twilight End | 17:18 |
| Nautical Twilight End | 17:55 |
| Astronomical Twilight End | 18:31 |
| Moon Illumination | 83.25% |