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AIM 

6/17/21 

5.  Wind. 

The wind is reported as a five digit 

group (six digits if speed is over 99 knots). The first 
three digits are the direction the wind is blowing 
from, in tens of degrees referenced to true north, or 
“VRB” if the direction is variable. The next two digits 
is the wind speed in knots, or if over 99 knots, the next 
three digits. If the wind is gusty, it is reported as a “G” 
after the speed followed by the highest gust reported. 
The abbreviation “KT” is appended to denote the use 
of knots for wind speed. 

EXAMPLE

 

13008KT 

 wind from 130 degrees at 8 knots 

08032G45KT 

 

wind from 080 degrees at 32 knots with 

gusts to 45 knots 
VRB04KT 

 wind variable in direction at 4 knots 

00000KT 

 wind calm 

210103G130KT 

 wind from 210 degrees at 103 knots with 

gusts to 130 knots 
If the wind direction is variable by 60 degrees or more and 
the speed is greater than 6 knots, a variable group 
consisting of the extremes of the wind direction separated 
by a “v” will follow the prevailing wind group. 
32012G22KT 280V350 

(a)  Peak Wind. 

Whenever the peak wind 

exceeds 25 knots “PK WND” will be included in 
Remarks, e.g., PK WND 28045/1955 “Peak wind two 
eight zero at four five occurred at one niner five five.” 
If the hour can be inferred from the report time, only 
the minutes will be appended, e.g., PK WND 
34050/38 “Peak wind three four zero at five zero 
occurred at three eight past the hour.” 

(b)  Wind shift. 

Whenever a wind shift 

occurs, “WSHFT” will be included in remarks 
followed by the time the wind shift began, e.g., 
WSHFT 30 FROPA “Wind shift at three zero due to 
frontal passage.” 

6.  Visibility. 

Prevailing visibility is reported in 

statute miles with “SM” appended to it. 

EXAMPLE

 

7SM 

 seven statute miles 

15SM 

 fifteen statute miles 

1

/

2

SM 

 one

half statute mile 

(a) Tower/surface visibility. 

If either visi-

bility (tower or surface) is below four statute miles, 

the lesser of the two will be reported in the body of the 
report; the greater will be reported in remarks. 

(b) Automated visibility. 

ASOS/AWOS 

visibility stations will show visibility 10 or greater 
than 10 miles as “10SM.” AWOS visibility stations 
will show visibility less than 

1

/

4

 statute mile as 

“M

1

/

4

SM” and visibility 10 or greater than 10 miles 

as “10SM.” 

NOTE

 

Automated sites that are augmented by human observer to 
meet service level requirements can report 0, 1/16 SM, and 
1/8 SM visibility increments. 

(c)  Variable visibility. 

Variable visibility is 

shown in remarks (when rapid increase or decrease 
by 

1

/

2

 statute mile or more and the average prevailing 

visibility is less than three miles) e.g., VIS 1V2 
“visibility variable between one and two.” 

(d)  Sector visibility. 

Sector visibility is 

shown in remarks when it differs from the prevailing 
visibility, and either the prevailing or sector visibility 
is less than three miles. 

EXAMPLE

 

VIS N2 

 visibility north two 

7.  Runway Visual Range (When Reported). 

“R” identifies the group followed by the runway 
heading (and parallel runway designator, if needed) 
“/” and the visual range in feet (meters in other 
countries) followed with “FT” (feet is not spoken). 

(a) Variability Values. 

When RVR varies 

(by more than on reportable value), the lowest and 
highest values are shown with “V” between them. 

(b)  Maximum/Minimum Range. 

“P” indi-

cates an observed RVR is above the maximum value 
for this system (spoken as “more than”). “M” 
indicates an observed RVR is below the minimum 
value which can be determined by the system (spoken 
as “less than”). 

EXAMPLE

 

R32L/1200FT 

 runway three two left R

V

R one thousand 

two hundred. 
R27R/M1000V4000FT 

 runway two seven right R

V

variable from less than one thousand to four thousand. 

7

1

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Meteorology