| Month | Average day | Declination (δ) | n |
| January | 17 | −20.9 | 17 |
| February | 16 | −13.0 | 47 |
| March | 16 | −2.4 | 75 |
| April | 15 | 9.4 | 105 |
| May | 15 | 18.8 | 135 |
| June | 11 | 23.1 | 162 |
| July | 17 | 21.2 | 198 |
| August | 16 | 13.5 | 228 |
| September | 15 | 2.2 | 258 |
| October | 15 | −9.6 | 288 |
| November | 14 | −18.9 | 318 |
| December | 10 | −23.0 | 344 |