| Φ | Equation | R2 |
| 6 - 10 | Twb = 0.4658Tdb − 2.177 | 0.8672 |
| 11 - 15 | Twb = 0.5506Tdb − 3.5846 | 0.8711 |
| 16 - 20 | Twb = 0.593Tdb − 3.5889 | 0.9144 |
| 21 -25 | Twb = 0.6456Tdb − 3.8737 | 0.9643 |
| 26 - 30 | Twb = 0.6845Tdb − 3.8201 | 0.9828 |
| 31 - 35 | Twb = 0.7277Tdb − 3.9253 | 0.9868 |
| 36 - 40 | Twb = 0.7555Tdb − 3.6281 | 0.9915 |
| 41 - 45 | Twb = 0.7876Tdb − 3.4778 | 0.9935 |
| 46 - 50 | Twb = 0.814Tdb − 3.2415 | 0.9944 |
| 51 - 55 | Twb = 0.8329Tdb − 2.8555 | 0.9957 |
| 56 - 60 | Twb = 0.8547Tdb − 2.5688 | 0.9965 |
| 61 - 65 | Twb = 0.8772Tdb − 2.3067 | 0.9971 |
| 66 - 70 | Twb = 0.8951Tdb − 1.9578 | 0.9973 |
| 71 - 75 | Twb = 0.9127Tdb − 1.6419 | 0.9974 |
| 76 - 80 | Twb = 0.9293Tdb − 1.327 | 0.9979 |
| 81 - 85 | Twb = 0.9464Tdb − 1.0134 | 0.998 |
| 86 - 90 | Twb = 0.9642Tdb − 0.7506 | 0.998 |
| 91 - 95 | Twb = 0.9772Tdb − 0.4249 | 0.9967 |
| 96 - 100 | Twb = 0.9852Tdb − 0.1798 | 0.9999 |