Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 279 | 244 | 274 | 252 | 248 | 240 |
| Tmin | 308 | 272 | 303 | 277 | 277 | 269 |
| Duration of sunshine | 52 | 54 | 65 | 59 | 58 | 54 |
| Precipitation | 126 | 112 | 124 | 121 | 129 | 120 |
| Humidity/Visibility | 113 | 102 | 114 | 103 | 112 | 108 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 252 | 273 | 263 | 263 | 257 | 270 |
| Tmin | 283 | 304 | 292 | 296 | 295 | 301 |
| Duration of sunshine | 64 | 81 | 74 | 60 | 46 | 35 |
| Precipitation | 126 | 159 | 152 | 147 | 121 | 130 |
| Humidity/Visibility | 117 | 138 | 135 | 128 | 110 | 116 |
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. |
