Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 798 | 730 | 810 | 791 | 835 | 809 |
| Tmin | 775 | 702 | 776 | 750 | 775 | 753 |
| Duration of sunshine | 0 | 0 | 0 | 0 | 0 | 0 |
| Precipitation | 78 | 66 | 68 | 85 | 99 | 99 |
| Humidity/Visibility | 21 | 32 | 36 | 43 | 58 | 60 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 830 | 842 | 806 | 841 | 802 | 835 |
| Tmin | 775 | 775 | 750 | 776 | 750 | 777 |
| Duration of sunshine | 0 | 0 | 0 | 0 | 0 | 0 |
| Precipitation | 106 | 110 | 95 | 100 | 102 | 122 |
| Humidity/Visibility | 57 | 59 | 56 | 61 | 53 | 58 |
Climate data is usually derived from meteorological data of a certain number of years. The actual number of recorded years may vary from only a couple to 50 years or more. The quality of climate data depends on the number of available recorded years. Fewer years means less reliable data. The standart-period for reliable climate data is 30 years. For example, the mean monthly temperature for, let's say January, would ideally calculated from a total number of 930 recorded January-days. However, the usual number of recorded days is much smaller. The table above shows the actual number of recorded days for every parameter measured. |
Anuradhapura