Understanding Preliminary Climate Data (Form CF-6)

Understanding Preliminary Climate Data (Form CF-6)

The preliminary climate data pages for Tallahassee and other sites consist of 18 columns of data, with one row of data for each day of the month. The day runs from 0000 to 2359 LST (0100 to 0059 during daylight time). The following is an excerpt from Tallahassee's WS Form F6 for November 2001. An explanation of each column of data can be found below the example. Columns are identified by bold numbers.

-1- Day	-2- Max	-3- Min	-4- Avg	-5- Dep.	-6a- HDD	-6b- CDD	-7- Water	-8- Snow	-9- Depth	-10- Avg.	-11- Speed	-12- Dir	-13- Mins.	-14- %PSBL	-15- SR-SS	-16- Weather	-17- Speed	-18- Dir

21	71	38	55	-3	10	0	0.00	0.0	N	2.4	8	300				1	15	310
22	72	38	55	-3	10	0	T	0.0	N	3.8	10	90				1,2	12	90
23	66	59	63	5	2	0	1.71	0.0	N	7.0	20	110				1,3	24	120
24	77	57	67	9	0	2	0.00	0.0	N	6.1	17	80				1	23	170
25	73	64	69	12	0	4	0.11	0.0	N	6.2	14	180				1,2	16	180

1	The date of the month.
2	The highest temperature for the day.
3	The lowest temperature for the day.
4	The average temperature for the day, computed by finding the average of the values in columns 2 and 3, then rounding up (if necessary).
5	Departure from normal. The difference between column 4 and the 30 year normal temperature for this date.
6a	Heating degree days. Computed by subtracting the average temperature from 65. If less than 0, HDD=0.
6b	Cooling degree days. Computed by subtracting 65 from the average temperature. If less than 0, CDD=0.
7	Total precipitation for the day to the nearest hundredth of an inch. This includes all forms of precipitation, both liquid and water equivalent of any snow or ice that occurred (T = Trace).
8	Total snowfall for the day to the nearest tenth of an inch.
9	Snow depth to the nearest inch at 7am EST (6am CST).
10	Average wind speed for the day in mph.
11	The highest wind speed in mph averaged over a 2 minute period.
12	The direction (in compass degrees divided by 10) from which the wind speed in column 11 came from. ( N=36 S=18 W=27 E=09, etc.)
13	The number of minutes of sunshine received at the station.*
14	The percentage of possible sunshine. Computed by dividing the minutes of sunshine in column 13 by the total possible minutes.*
15	The average sky cover between sunrise and sunset in tenths.*
16	A coded number representing certain types of weather observed during the day. The codes can be found near the bottom of the F6 form itselft (e.g., 3 = Thunder).
17	Peak wind speed for the day in mph. The highest wind speed observed at the station.
18	The compass direction from which the peak wind speed came.

* Not included in our reports.

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