| | | | | | | | | | | | |
|
| Birr 1979-2008 averages
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| TEMPERATURE (degrees Celsius) | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| mean daily max | 8.1 | 8.6 | 10.3 | 12.6 | 15.5 | 17.8 | 19.6 | 19.3 | 17.1 | 13.6 | 10.4 | 8.6 | 13.5 |
| mean daily min | 2.0 | 2.0 | 3.3 | 4.3 | 6.6 | 9.5 | 11.6 | 11.3 | 9.3 | 6.6 | 4.0 | 2.7 | 6.1 |
| mean temperature | 5.1 | 5.3 | 6.8 | 8.4 | 11.0 | 13.6 | 15.6 | 15.3 | 13.2 | 10.1 | 7.2 | 5.6 | 9.8 |
| absolute max. | 14.3 | 15.5 | 18.6 | 23.2 | 25.7 | 29.7 | 30.8 | 29.4 | 25.6 | 20.4 | 17.5 | 15.3 | 30.8 |
| min. maximum | -3.5 | -0.5 | 2.0 | 4.3 | 6.3 | 10.5 | 12.5 | 11.6 | 9.7 | 5.9 | 2.7 | -1.0 | -3.5 |
| max. minimum | 11.6 | 12.1 | 12.2 | 13.0 | 15.2 | 16.6 | 18.9 | 18.1 | 17.9 | 15.7 | 12.8 | 13.0 | 18.9 |
| absolute min. | -14.6 | -7.1 | -7.8 | -4.7 | -2.3 | 0.2 | 3.7 | 2.0 | -1.1 | -5.2 | -6.9 | -8.6 | -14.6 |
| mean num. of days with air frost | 8.2 | 7.7 | 4.9 | 3.5 | 0.9 | 0.0 | 0.0 | 0.0 | 0.2 | 1.6 | 4.8 | 7.0 | 38.8 |
| mean num. of days with ground frost | 16.0 | 15.0 | 13.0 | 12.0 | 7.0 | 1.0 | 0.0 | 0.0 | 2.0 | 6.0 | 11.0 | 15.0 | 98.0 |
| mean 5cm soil | 3.9 | 3.9 | 5.7 | 9.0 | 13.0 | 16.0 | 17.2 | 16.4 | 13.5 | 9.4 | 6.2 | 4.5 | 9.9 |
| mean 10cm soil | 4.1 | 4.2 | 5.6 | 8.2 | 11.8 | 14.8 | 16.3 | 15.6 | 13.0 | 9.4 | 6.5 | 4.8 | 9.5 |
| mean 20cm soil | 4.8 | 5.0 | 6.4 | 8.8 | 12.1 | 14.9 | 16.6 | 16.2 | 14.0 | 10.5 | 7.5 | 5.6 | 10.2 |
| RELATIVE HUMIDITY (%) | | | | | | | | | | | | | |
| mean at 0900UTC | 89.8 | 88.9 | 86.9 | 81.5 | 77.7 | 78.3 | 80.9 | 84.2 | 86.6 | 89.1 | 90.9 | 90.3 | 85.4 |
| mean at 1500UTC | 82.4 | 75.6 | 71.6 | 65.1 | 64.7 | 66.2 | 67.5 | 68.5 | 70.3 | 76.1 | 81.1 | 84.5 | 72.8 |
| SUNSHINE (hours) | | | | | | | | | | | | | |
| mean daily duration | 1.5 | 2.2 | 2.9 | 4.5 | 5.1 | 4.3 | 3.9 | 4.0 | 3.5 | 2.9 | 1.9 | 1.4 | 3.2 |
| greatest daily duration | 7.7 | 9.4 | 10.5 | 13.0 | 15.1 | 15.7 | 15.2 | 13.6 | 11.5 | 9.7 | 8.5 | 6.9 | 15.7 |
| mean num. of days with no sun | 11.0 | 7.1 | 5.8 | 2.9 | 2.2 | 2.9 | 2.5 | 2.5 | 3.5 | 6.2 | 8.8 | 12.0 | 67.4 |
| RAINFALL (mm) | | | | | | | | | | | | | |
| mean monthly total | 78.8 | 58.6 | 67.4 | 55.0 | 59.5 | 66.5 | 59.4 | 81.6 | 66.4 | 94.2 | 74.7 | 83.8 | 845.7 |
| greatest daily total | 39.2 | 28.0 | 22.0 | 26.3 | 19.7 | 41.1 | 44.5 | 59.1 | 35.7 | 32.3 | 29.7 | 37.5 | 59.1 |
| mean num. of days with >= 0.2mm | 19 | 15 | 19 | 15 | 16 | 16 | 16 | 18 | 17 | 19 | 18 | 18 | 206 |
| mean num. of days with >= 1.0mm | 14 | 11 | 14 | 11 | 12 | 11 | 11 | 12 | 11 | 14 | 13 | 13 | 147 |
| mean num. of days with >= 5.0mm | 5 | 4 | 4 | 3 | 4 | 4 | 3 | 5 | 4 | 6 | 5 | 6 | 53 |
| WIND (knots) | | | | | | | | | | | | | |
| mean monthly speed | 7.9 | 8.0 | 7.8 | 6.5 | 6.2 | 5.8 | 5.6 | 5.6 | 6.0 | 6.8 | 7.0 | 7.5 | 6.7 |
| max. gust | 75 | 77 | 64 | 58 | 55 | 49 | 49 | 46 | 51 | 64 | 54 | 69 | 59.2 |
| max. mean 10-minute speed | 40 | 38 | 33 | 29 | 29 | 27 | 24 | 27 | 30 | 37 | 32 | 38 | 32 |
| mean num. of days with gales | 0.2 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.5 |
| WEATHER (mean no. of days with..) | | | | | | | | | | | | | |
| snow or sleet | 3.5 | 2.6 | 2.5 | 0.8 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 1.9 | 11.7 |
| snow lying at 0900UTC | 2.0 | 0.6 | 0.7 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.3 | 3.7 |
| hail | 0.6 | 0.8 | 1.8 | 2.0 | 0.9 | 0.1 | 0.0 | 0.2 | 0.1 | 0.2 | 0.3 | 0.3 | 7.3 |
| thunder | 0.1 | 0.1 | 0.2 | 0.3 | 0.4 | 0.8 | 0.9 | 0.5 | 0.3 | 0.1 | 0.2 | 0.1 | 3.9 |
| fog | 2.1 | 1.3 | 1.1 | 1.5 | 1.1 | 0.8 | 1.1 | 1.8 | 2.5 | 2.1 | 1.9 | 2.9 | 20.4 |