Sneyers, R., Vandiepenbeeck, M. & Vanlierde, R. Theor Appl Climatol (1992) 45: 61. doi:10.1007/BF00865995
A principal component analysis has been performed on the monthly means of the daily extremes of the air temperature at the thermometric network of Belgium. For both the maximum and the minimum temperatures, two components are found to have a climatological significance, the first one giving the common seasonal variation. For the maximum, the second component depends directly on the proximity of the sea, while for the minimum, the second component gives the correction due partly to the proximity of the sea and partly to the site configuration of the station (plateau or valley). In both cases, the variance explained by the two components amounts to or exceeds 99.9% of the total variance.