showing a 30° C variation. On the other hand, during January and February, 

 the average high and low temperatures were most nearly the same, showing only 

 a 5° to 6° C difference. These tendencies reflect the complex interaction of 

 (a) sea temperature, which varies slowly; (b) wind direction, which can change 

 very quickly; and (c) winter air systems, which can come from the Arctic air 

 masses to the north or from the tropical maritime air mass to the south. The 

 opposite is true during the warm months of June through September when the 

 temperature variation was 23° C (versus 30° C in February) and the average 

 highs and lows varied by as much as 9° C in July, compared with 5° to 6° C in 

 January and February. 



90. Precipitation (See Table 4) . A total of 793 mm of precipitation 

 was measured during 1980, 400 mm less than during 1979. Table 5 shows the 

 monthly means, maxima, and minima from 1978 through 1980 at the FRF; absent 

 during 1980 were monthly rainfalls in excess of 125 mm, as occurred in 1979 

 during January (180), May (239), and September (160), and in 1978 during March 

 (137), May (145), June (130), and November (130). April was the wettest month 

 of 1980, with 112 mm of rain measured; September was the driest month, with 

 30 mm of rainfall. 1980 totals were the lowest in 7 of the months and the 

 highest in 3 others. 



Table 5 

 Monthly Precipitation Means, Maxima, and Minima at 





the 



FRF from 



1978 Through 



1980 















Monthly 





Maxima 





Minima 





Mean 



Month 



mm 



Year 

 1979 



mm 



Year 

 1980 



1978-80 



Jan 



180 



89 



135 



Feb 



94 



1979 



66 



1980 



80 



Mar 



137 



1978 



64 



1979 



97 



Apr 



112 



1980 



71 



1979 



86 



May 



239 



1979 



39 



1980 



141 



Jun 



130 



1978 



60 



1980 



87 



Jul 



104 



1978 



64 



1980 



79 



Aug 



48 



1979 



and 



1980 



36 



1978 



44 



Sep 



160 



1979 



13 



1978 



68 



Oct 



73 



1980 



25 



1978 



51 



Nov 



130 



1978 



96 



1980 



108 



Dec 



84 



1978 



47 



1980 



60 



38 



