Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 137 | 110 | 143 | 137 | 154 | 144 |
| Tmin | 134 | 127 | 140 | 135 | 147 | 143 |
| Duration of sunshine | 102 | 87 | 109 | 112 | 123 | 105 |
| Precipitation | 153 | 141 | 154 | 158 | 164 | 154 |
| Humidity/Visibility | 101 | 87 | 106 | 104 | 111 | 108 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 147 | 166 | 161 | 157 | 155 | 140 |
| Tmin | 143 | 163 | 167 | 152 | 141 | 141 |
| Duration of sunshine | 104 | 125 | 146 | 121 | 107 | 121 |
| Precipitation | 165 | 196 | 204 | 190 | 185 | 167 |
| Humidity/Visibility | 112 | 123 | 116 | 118 | 114 | 106 |
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. |
