This shows the percentage of occasions that the minimum visibility fell below certain limits, by month. Weather such as fog, thunderstorms and snow are all important for pilots. This shows the percentage of days that certain important weather conditions were reported, by month. The relevance to pilots is due to the fact that their operating minima involves cloud bases. This displays the frequency occurrence, since the record began, that a cloud base (over half cover) fell below certain altitudes, by month. Temperatures are useful to pilots when considering fuel loads and icing. The sum total of these ranges always equals 100%.

This shows the percentage of occasions that the daily maximum temperature fell within certain ranges, by month. Some aircraft have restricted use in LVP conditions. (Low Visibility Procedures) - When the cloud base and visibility both fall below certain limits (such as 1,500 m for visibility and 3,000 ft for cloud), the operating 2 conditions at the airport change and new rules are imposed. This data is historical and provides an indication of average weather conditions at each site, consequently valid pre-flight briefing documentation still needs to be obtained for each flight. By looking at the different sites, you will be able to determine which of several airfields will best meet your needs. This will show you how often on average you might have problems with crosswinds. So, for example, the wind rose will show you the prevailing wind at each site.

Graphs of averages are then produced which help you understand the data. The statistics on these pages are derived from weather observations made over a number of years by meteorological observers at each airfield.

Annual wind rose diagram