| Geyser | 1931-07-31 |
|---|---|
| Dark Cavern | 0900, 1530 |
| Pinto | 1125 |
| Valentine | 1030 |
| Values for Old Faithful Area | 1931-07-31 |
|---|---|
| Astronomical Twilight Begin | 03:03 |
| Nautical Twilight Begin | 03:52 |
| Civil Twilight Begin | 04:34 |
| Sunrise | 05:08 |
| Sunset | 19:50 |
| Civil Twilight End | 20:24 |
| Nautical Twilight End | 21:06 |
| Astronomical Twilight End | 21:55 |
| Moon Illumination | 97.02% |