| Dekaden Messwerte & Standardabweichung* 2021 für Willich / Niederrhein (Stand: 31.12.2021 18:12 Uhr ) 
 | 
| Mitteltemperatur 
 | 
| Monat/Tag | 1-10 | 11-20 | 21-31 | Monat | 
|  | Mittelwert | STDV | Mittelwert | STDV | Mittelwert | STDV | Mittelwert | STDV | 
| Januar | 1.8 °C | -1.1
 °C | 3.3 °C | +0.7
 °C | 3.8 °C | +1.0
 °C | 3.0 °C | +0.5
 °C | 
| Februar | 1.8 °C | -1.1
 °C | 2.6 °C | -0.6
 °C | 11.0 °C | +7.0
 °C | 4.7 °C | +1.5
 °C | 
| März | 5.2 °C | +0.3
 °C | 6.0 °C | +0.2
 °C | 10.4 °C | +3.6
 °C | 7.3 °C | +1.5
 °C | 
| April | 6.4 °C | -1.6
 °C | 7.3 °C | -1.9
 °C | 9.8 °C | -0.8
 °C | 7.8 °C | -1.4
 °C | 
| Mai | 11.1 °C | -0.9
 °C | 12.9 °C | -0.7
 °C | 13.5 °C | -1.0
 °C | 12.5 °C | -1.1
 °C | 
| Juni | 20.4 °C | +4.9
 °C | 23.6 °C | +7.0
 °C | 18.8 °C | +1.8
 °C | 20.9 °C | +4.3
 °C | 
| Juli | 18.6 °C | +1.1
 °C | 19.7 °C | +1.5
 °C | 19.9 °C | +2.0
 °C | 19.4 °C | +1.2
 °C | 
| August | 17.8 °C | +0.0
 °C | 18.6 °C | +0.8
 °C | 17.3 °C | +0.5
 °C | 17.9 °C | +0.0
 °C | 
| September | 18.8 °C | +2.9
 °C | 17.1 °C | +1.9
 °C | 15.0 °C | +1.3
 °C | 16.9 °C | +1.8
 °C | 
| Oktober | 13.0 °C | +0.5
 °C | 11.0 °C | -0.4
 °C | 10.7 °C | +1.1
 °C | 11.5 °C | +0.2
 °C | 
| November | 7.5 °C | -0.4
 °C | 7.2 °C | +0.8
 °C | 4.1 °C | -1.3
 °C | 6.3 °C | -0.1
 °C | 
| Dezember | 4.0 °C | -0.5
 °C | 6.6 °C | +3.0
 °C | 5.4 °C | +2.2
 °C | 5.3 °C | +1.7
 °C | 
| Jahr | STDV-Abweichung | 11.2  °C | +0.86  °C | 
| Niederschlag 
 | 
| Monat/Tag | 1-10 | 11-20 | 21-31 | Monat | 
|  | Summe | STDV | Summe | STDV | Summe | STDV | Summe | STDV | 
| Januar | 11.4 l/m² | -10.4
 l/m² | 23.6 l/m² | +2.3
 l/m² | 58.0 l/m² | +38.7
 l/m² | 93.0 l/m² | +29.2
 l/m² | 
| Februar | 33.4 l/m² | +15.9
 l/m² | 17.4 l/m² | +1.5
 l/m² | 4.0 l/m² | -13.5
 l/m² | 54.8 l/m² | +7.3
 l/m² | 
| März | 21.8 l/m² | +2.6
 l/m² | 22.2 l/m² | +0.9
 l/m² | 1.8 l/m² | -17.9
 l/m² | 45.8 l/m² | -17.9
 l/m² | 
| April | 18.0 l/m² | -0.3
 l/m² | 12.2 l/m² | -5.0
 l/m² | 0.6 l/m² | -18.5
 l/m² | 30.8 l/m² | -20.7
 l/m² | 
| Mai | 16.4 l/m² | -4.8
 l/m² | 32.2 l/m² | +8.7
 l/m² | 13.6 l/m² | -11.0
 l/m² | 62.2 l/m² | -8.5
 l/m² | 
| Juni | 15.6 l/m² | -10.3
 l/m² | 6.0 l/m² | -21.5
 l/m² | 84.6 l/m² | +58.3
 l/m² | 106.2 l/m² | +23.7
 l/m² | 
| Juli | 28.2 l/m² | +3.0
 l/m² | 73.4 l/m² | +48.9
 l/m² | 23.2 l/m² | +1.3
 l/m² | 124.8 l/m² | +51.3
 l/m² | 
| August | 21.0 l/m² | +1.3
 l/m² | 7.6 l/m² | -9.9
 l/m² | 24.4 l/m² | +6.8
 l/m² | 53.0 l/m² | +0.5
 l/m² | 
| September | 5.0 l/m² | -12.8
 l/m² | 4.8 l/m² | -13.5
 l/m² | 14.4 l/m² | -3.6
 l/m² | 24.2 l/m² | -30.7
 l/m² | 
| Oktober | 18.2 l/m² | +0.2
 l/m² | 17.2 l/m² | -0.9
 l/m² | 26.0 l/m² | +6.7
 l/m² | 61.4 l/m² | +7.2
 l/m² | 
| November | 5.6 l/m² | -15.1
 l/m² | 6.8 l/m² | -15.5
 l/m² | 16.2 l/m² | -6.3
 l/m² | 28.6 l/m² | -38.5
 l/m² | 
| Dezember | 20.2 l/m² | -2.7
 l/m² | 6.4 l/m² | -17.1
 l/m² | 30.0 l/m² | +7.4
 l/m² | 56.6 l/m² | -14.0
 l/m² | 
| Jahr | STDV-Abweichung | 741.4  l/m² | -11.1  l/m² | 
| Sonnenstunden 
 | 
| Monat/Tag | 1-10 | 11-20 | 21-31 | Monat | 
|  | Summe | STDV | Summe | STDV | Summe | STDV | Summe | STDV | 
| Januar | 1.17 h | -13.3
 h | 4.37 h | -10.6
 h | 18.03 h | -0.4
 h | 23.57 h | -21.5
 h | 
| Februar | 10.43 h | -11.5
 h | 34.03 h | +8.3
 h | 35.87 h | +7.1
 h | 80.33 h | +3.2
 h | 
| März | 44.77 h | +12.5
 h | 39.27 h | +3.3
 h | 70.70 h | +30.0
 h | 154.73 h | +46.7
 h | 
| April | 44.87 h | -0.9
 h | 54.67 h | +3.4
 h | 78.98 h | +23.4
 h | 178.52 h | +24.4
 h | 
| Mai | 55.63 h | -4.7
 h | 48.20 h | -17.5
 h | 71.98 h | +7.8
 h | 175.82 h | -21.2
 h | 
| Juni | 72.17 h | +8.9
 h | 105.63 h | +42.6
 h | 46.20 h | -16.8
 h | 224.00 h | +34.9
 h | 
| Juli | 52.20 h | -11.3
 h | 52.40 h | -12.3
 h | 80.13 h | +16.8
 h | 184.73 h | -9.4
 h | 
| August | 46.12 h | -16.4
 h | 48.78 h | -13.5
 h | 53.40 h | -3.0
 h | 148.30 h | -38.8
 h | 
| September | 61.97 h | +11.1
 h | 40.73 h | -5.3
 h | 36.50 h | -6.2
 h | 139.20 h | +1.1
 h | 
| Oktober | 29.48 h | -10.4
 h | 18.63 h | -18.7
 h | 24.03 h | -6.8
 h | 72.15 h | -39.9
 h | 
| November | 16.97 h | -7.7
 h | 8.00 h | -10.7
 h | 8.00 h | -9.0
 h | 32.97 h | -23.1
 h | 
| Dezember | 8.17 h | -7.2
 h | 4.47 h | -9.5
 h | 8.77 h | -5.4
 h | 21.40 h | -20.6
 h | 
| Jahr | STDV-Abweichung | 1435.72  h | -61.9  h | 
| *STDV-Dekadenwerte interpoliert | 
| Script Matthias Krücke www.woldegk-wetter.de |