[s1artibartfast]

The paper seems to say the opposite:

>This reflects the variation in temperatures and wind speeds with season, with calmer, warmer conditions in summer and cooler, windier conditions in late autumn and early spring. However above the 75th percentile of demand, average wind power reduces, which occurs predominantly in winter and autumn. Understanding this downturn in wind power provides the motivation for this paper. Given our interest in high demand days, which predominantly occur in winter (figure 1, upper right), only winter days are considered.

>The tendency for lower wind power during higher winter demand is shown by the tilt of the density contours of the daily distribution (figure 1, lower left). It is also clearly seen when averaged across days of similar demand (figure 2, left). Average wind power reduces by a third between lower and higher winter demand, from approximately 60% to 40% of rated power.

Look at figure 2. Black is wind power, and the X axis is demand. Wind production capacity is down when demand is high.

[cycomanic]

Ok my statement was largely based on the abstract, I only skimmed the paper. The abstract refers to the uptick for very high demand percentiles (>90%), which I guess is still much smaller than the downward trend. I apologise I got this wrong.

[nickdothutton]

The very cold days in winter in the UK are always still days.

[stoobs]

From direct experience, this is incorrect.

The vast majority of the UK's cold winter weather comes from wind from the North-East, bringing in the much colder weather from Arctic/Siberian regions.