Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 186 | 168 | 186 | 180 | 186 | 180 |
| Tmin | 232 | 216 | 233 | 238 | 239 | 244 |
| Duration of sunshine | 41 | 38 | 41 | 58 | 54 | 62 |
| Precipitation | 117 | 127 | 132 | 140 | 158 | 153 |
| Humidity/Visibility | 23 | 31 | 32 | 40 | 44 | 46 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 186 | 186 | 180 | 186 | 180 | 186 |
| Tmin | 232 | 234 | 236 | 237 | 226 | 242 |
| Duration of sunshine | 44 | 46 | 54 | 48 | 41 | 55 |
| Precipitation | 172 | 152 | 134 | 144 | 165 | 179 |
| Humidity/Visibility | 44 | 41 | 40 | 38 | 32 | 45 |
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. |
Arusha