| Month | Maximum mean rainfall (mm) | Observed year | Coefficient of determination (%) |
| April | 52.6 | 2011 | 72.38 |
| May | 144.5 | 2007 | 86.63 |
| June | 110.2 | 2011 | 20.8 |
| July | 102.4 | 2011 | 44.21 |
| August | 73.4 | 2011 | 6.91 |
| September | 121.7 | 2008 | 70.6 |