Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 183 | 167 | 186 | 177 | 184 | 176 |
| Tmin | 184 | 166 | 186 | 178 | 185 | 176 |
| Duration of sunshine | 184 | 165 | 186 | 178 | 185 | 174 |
| Precipitation | 186 | 168 | 186 | 181 | 186 | 184 |
| Humidity/Visibility | 182 | 167 | 185 | 177 | 184 | 174 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 177 | 181 | 205 | 203 | 204 | 217 |
| Tmin | 177 | 186 | 206 | 207 | 207 | 215 |
| Duration of sunshine | 176 | 186 | 206 | 207 | 206 | 215 |
| Precipitation | 183 | 190 | 210 | 214 | 209 | 219 |
| Humidity/Visibility | 178 | 182 | 205 | 205 | 206 | 214 |
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. |
