Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 1240 | 1149 | 1270 | 1225 | 1255 | 1229 |
| Tmin | 1239 | 1143 | 1269 | 1225 | 1258 | 1226 |
| Duration of sunshine | 240 | 266 | 296 | 274 | 351 | 312 |
| Precipitation | 186 | 169 | 189 | 181 | 188 | 180 |
| Humidity/Visibility | 184 | 166 | 184 | 177 | 183 | 178 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 1265 | 1269 | 1252 | 1291 | 1256 | 1300 |
| Tmin | 1269 | 1272 | 1256 | 1294 | 1257 | 1297 |
| Duration of sunshine | 350 | 312 | 301 | 346 | 332 | 289 |
| Precipitation | 186 | 190 | 210 | 215 | 210 | 219 |
| Humidity/Visibility | 184 | 185 | 206 | 209 | 205 | 213 |
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. |
Gibraltar