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SUMMARY

Cloud was recorded as tenths of sky area until end of February 1949 and recorded in eighths after this date. In this analysis, all the data have been converted to percentage of sky clouded.

There is no significant change in cloud cover either for the annual average or for the average over the four quarters of each year.

There is certainly no evidence of increased stormy weather, as predicted by climate change models and which we would expect to see as increasing cloud cover.

ANALYSIS

Figure 1

Figure 1 shows the annual average cloud cover. It can be seen that the change from recording in 'tenths of sky' to 'eighths of sky' in 1949 did not produce any significant discontinuity in the data.

It can be seen that there is no significant change in cloud cover from 1927 to 2005.

Figure 2

Figure 2 shows the average cloud cover in the first quarter of each year (black curve) with the five-year running average shown by the red curve. There is a merest hint of increasing cloud cover but this is not significant.

Figure 3

Figure 3 shows the average cloud cover in the second quarter of each year (black curve) with the five-year running average shown by the red curve. As for the first quarter, there is a hint of increasing cloud cover but this is not significant.

Figure 4

Figure 4 shows the average cloud cover in the third quarter of each year (black curve) with the five-year running average shown by the red curve. There is no significant change over the years.

Figure 5

Figure 5 shows the average cloud cover in the first quarter of each year (black curve) with the five-year running average shown by the red curve. There is no significant change over the years.

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