Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 652 | 594 | 653 | 640 | 652 | 626 |
| Tmin | 658 | 596 | 649 | 637 | 645 | 635 |
| Duration of sunshine | 117 | 103 | 109 | 118 | 111 | 105 |
| Precipitation | 165 | 152 | 167 | 165 | 161 | 156 |
| Humidity/Visibility | 129 | 114 | 124 | 123 | 117 | 122 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 650 | 659 | 653 | 668 | 661 | 689 |
| Tmin | 664 | 659 | 661 | 664 | 675 | 688 |
| Duration of sunshine | 126 | 117 | 130 | 115 | 146 | 139 |
| Precipitation | 164 | 162 | 184 | 183 | 184 | 195 |
| Humidity/Visibility | 130 | 125 | 143 | 133 | 153 | 158 |
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. |
