CLOUD OCCURRENCE 



RELATIVE 

 HUMIDITY RANGE 



100 



90 



80 



70 - 



50 





60 - ± 1 



J FMAMJJ ."• S O N D 

 Months 



MEAN TOTAL 

 PRECIPITATION 



6 



5 - 

 4 

 3 



2 



1 - 



JFMAMJJ ASOND 

 Months 



100 

 90 

 80 

 70 

 60 

 % 50 

 40 

 30 

 20 

 10 

 



CloudyS 



Partly Cloudy 



Clear 



' ' I ' ' ' ' ' I ' I I 



JFMAMJJASOND 



Months 



PORTLAND 

 1941-1970 



J FMAMJ J ASOND 

 Months 



TEMPERATURE 



110 



100 



90 



80 



70 



60 



50 



40 



30 



20 



10 







-10 



-20 



-30 



-40 



1 v 



i 



i 



ii 1 /'*. l 



• 



1*1111111111 



J FMAMJ J ASOND 

 Months 



" 



Figure 2-9. Summary of basic climate parameters at Portland. 



2-18 



