WEATHER 43 



give a complete description of the weather during the preceding 6 hours. 

 When the weather occurring at the time of the observation (rather than the 

 hour before it) is coded as "ww," the weather during the full 6 hours prior 

 to the time of the observation must be coded as "W." When the weather 

 that has occurred during the hour ending with the observation is coded as 

 "ww," weather during the 5 hours preceding the hour covered by "ww" will 

 be coded as "W." For example, if a rain shower has occurred during the 

 hour preceding the 0600 GCT observation, and the weather was generally 

 cloudy during the entire 6-hour period prior to the observation, "ww" would 

 be coded as 25, and "W" as 2, If showers were general throughout the 

 6-hour period, including the hour before the observation, "ww" would be 

 coded as 25, and "W" as 8. When precipitation has occurred during the 6 

 hours preceding the time of the observation, but has not occurred during 

 the hour preceding the observation, code figures 5, 6, 7, 8 or 9, as appro- 

 priate, will be used for "W," 



5821. When thunder has been heard during the 6- hour period before 

 the observation, but too early to be coded as "ww," "W" will always be 

 coded as 9, regardless of other aspects of the weather. In general, when 

 two or more code figures are appropriate for symbol "W," the highest 

 figure will be used. 



