Surface Wind
( Measured at 10 m )
( m / sec. )
Surface Wind
( Measured at 10 m )
( mph )
Day 
Incoming Solar Radiation**
( Insolation )
( Strong )
Day 
Incoming Solar Radiation**
( Insolation )
( Moderate )
Day 
Incoming Solar Radiation**
( Insolation )
( Slight )
Night*
( Thin Overlast 
or
>= 4/8 cloudiness* )
Night*
( <= 3/8 cloudiness* )
< 2
< 4.5
A
A-B
B
F
F
2 - 3
4.5 - 6.7
A-B
B
C
E
F
3 - 5
6.7 - 11.2
B
B-C
C
D
E
5 - 6
11.2 - 13.4
C
C-D
D
D
D
6
13.4
C
D
D
D
D