| Geyser | 1999-10-31 |
|---|---|
| Grand | 0214 E, 1123 E |
| Great Fountain | 0349 E, 1347 E, 2330 E |
| Values for Old Faithful Area | 1999-10-31 |
|---|---|
| Astronomical Twilight Begin | 05:21 |
| Nautical Twilight Begin | 05:54 |
| Civil Twilight Begin | 06:29 |
| Sunrise | 06:59 |
| Sunset | 17:14 |
| Civil Twilight End | 17:44 |
| Nautical Twilight End | 18:19 |
| Astronomical Twilight End | 18:52 |
| Moon Illumination | 52.98% |