Weather data file explanation

weather.dat contains meteorological observations for
nearly every hour of every day for Fort Collins, Colorado
for the year 1999. Each line of the file represents a
separate hourly observation; the information on each
line is slightly compressed. Every line of the file
is exactly 28 characters long.

Here is a sample line from the file. Every line has
exactly the same format.

199901011300+043055011017632

This is how to understand this and every other line,
the first 12 characters give the date and time of the
observation, the rest give the data values.


characters  sample  meaning

  1-4        1999   the year, always 1999 in this file
  5-6        01     the month, 01=January 12=December
  7-8        01     the day, in the range 01 to 31
  9-12       1300   the time, 1300 is of course 1 p.m.

 13-16       +043   temperature in degrees fahrenheit
                    always + or - then three digits

 17-19       055    humidity, a percentage, 3 digits

 20-22       011    average wind speed, miles per hour
                    always three digits

 23-25       017    average wind direction, in degrees
                    always three digits
                    0=North, 90=East, 180=South, etc

 26-28       632    atmospheric pressure always 3 digits
                    in millimitres of Mercury (mmHg)

So the example line says that in Fort Collins, Colorado,
at 1.00 pm on the 1st of January 1999:
  the temperature was 43 degrees fahrenheit,
  there was 55% humidity
  the wind was blowing at 11 mph from the North North East,
  the pressure was 632 mmHg (or 24.9 inHg).

Note that the file contains 8750 lines of data, but
365 x 24 is 8760, so there are a few observations missing.