Comment on “Winter ‘weekend effect’ in southern Europe and its connection with periodicities in atmospheric dynamics” by A. Sanchez‐Lorenzo et al.

[1] There is an on-going scientific debate whether meteorological variables show a weekly cycle or not. SanchezLorenzo et al. [2008] (hereinafter referred to as SL08) find a significant weekly cycle in Spanish meteorological data and argue that this cycle is linked with a weekly cycle in European air pressure (pair) distributions. Their two main arguments are: 1) The Spanish pair data show a significant weekly cycle, 2) The frequency of circulation pattern number 3 (with an anticyclone above the British Islands) shows a significant difference between Sunday and Monday on one hand and Wednesday on the other hand. [2] In this paper, we present our analysis of the Spanish pair data, based on Monte Carlo (MC) analysis, nonparametric tests and Fourier analysis and conclude that no significant weekly cycle in these data is present. It is explained why SL08 find a significant cycle and what was, in our opinion, the reason that they came to this erroneous conclusion. It is also argued that the second main argument of SL08 for a weekly cycle (on the basis of circulation patterns over Europe) is the result of a misinterpretation of the statistical test results.