How To Read Climate Forms (F6)


The climate information provided has 18 columns of information. All are based on information gathered from midnight to midnight Central Standard Time (CST). The following is a brief description of each column:

M - Indicates information is missing or unavailable

Column 1 (Dy) - The day of the month

Column 2 (Max) - High temperature for the date.

Column 3 (Min) - Low Temperature for the date.

Column 4 (Avg) - Average Temperature for the date.

Column 5 (Dep) - Departure from normal. In other words, how many degrees above or below normal the average temperature was for that date. Negative implies below normal, while an absence of sign indicates above normal.

Column 6a (HDD) - Heating Degree Days. Based on how many degrees below 65 the average temperature was. This information is useful for utility companies and certain other industries that track power consumption.

Column 6b (CDD) - Cooling Degree Days. Based on how many degrees above 65 the average temperature was. Like column 6a, also useful to companies interested in power consumption.

Column 7 (Wtr) - Daily precipitation. The liquid equivalent of the rainfall/snowfall/sleet/hail that fell on a particular day. For our area, this is most often the total daily rainfall. Measured to the nearest hundredth of a inch (0.01").

Column 8 (Snw) - Snowfall. The amount of snow or ice that fell on that date. Measured to the nearest tenth of an inch (0.1").

Column 9 (Dpth) - Snow Depth. Measured at noon on that date, the amount of ice or snow that has accumulated on the ground at that time. Not necessarily the same as Column 8, particularly on days that are near or above freezing. We get measureable snowfall/ice on the ground about once a decade.

Column 10 (Avg) - Average wind velocity for the date. Reported to the nearest tenth of a mile per hour (0.1 mph).

Column 11 (Spd) - Maximum sustained (2-minute average) wind measured during that day. Reported to the nearest mile per hour (1 mph).

Column 12 (Dir) - Average Wind direction for that date. Measured in degrees around, clockwise from due north. Thus, north is 360 or 0 degrees, east 90 degrees, south 180 degrees, and west is 270 degrees. All other wind directions fall in between these values.

Column 13 (Min) - Minutes of sunshine measured by our sunshine counter for that date.

Column 14 (Psbl) - Percent of possible sunshine for the date. One hundred percent corresponds to the length of the solar day, from sunrise to sunset.

Column 15 (S-S) - Sky condition from sunrise to sunset, reported to nearest okta. Not calculated for sites that are automated.

Column 16 (Wx) - Weather. Indicates the type of weather that occurred on that day. The following shows that the numbers and symbols in that column stand for:

1 = Fog reducing visibility under 7 miles, but above 1/4 mile.
2 = Fog reducing visibility to 1/4 of a mile or less
3 = Thunder reported at station
4 = Ice Pellets / Sleet
5 = Hail (Graupel)
6 = Glaze or rime (Ice accumulated during the day)
7 = Blowing dust or sand reducing vsisibility to 1/2 mile or less
8 = Smoke or Haze
9 = Blowing Snow
X = Tornado / Funnel Cloud / Waterspout seen from station

Column 17 (Spd) - Peak wind gust for date measured in miles per hour (mph).

Column 18 (Dr) - Direction from which peak gust occurred, measured in degrees. North is 360 or 0, east is 90, south is 180, west is 270. All other directions fall in between. is the U.S. government's official web portal to all federal, state and local government web resources and services.
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  • Detroit/Pontiac, MI Weather Forecast Office
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  • White Lake, MI 48386
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  • Page last modified: 3-Aug-2007 12:48 PM UTC