Description of Data

The climate data contained here is obtained from hourly observations used in operational forecasting. It is not official because of potential gaps in the data due to problems with communications etc. and because of potential errors which are not later corrected. The acquisition of this information is totally automated.

But inspite of this in most cases it is resonably accurate and many daily climate observations here are not available elsewhere on the internet.

The data begins with the end of May 1997 unless otherwise noted. Each day of the month has an entry on one line. Data for a day for most of the parameters is for the period midnight to midnight EST (1 AM to 1 AM EDT). But total precipitation uses the period 1 AM to 1 AM EST (2 AM to 2 AM EDT). Before about June 23 1997 precipitation was from 8 PM to 8 PM EST. Data between September 11, 1997 and September 17 1997 is incomplete due to problems with the computer that acquires the data, it mainly affects maximum temperatures and data that occurred during the daylight hours.

The following abbreviations are used:
Dy: Day of Month
Mxt: The highest temperature of the day.
Mnt: The lowest temperature of the day.
AvT: The average daily temperature (the sum of MxT and MnT divided by 2.
HrlyT: The average of the hourly temperatures for each hour of the day. In most cases it is about the same as AvT.
HDDay: The heating degree days. This is obtained by subtracting AvT from 65. Negative values are set to zero.
AvDP: The average of the dew point for each hour of the day.
1HrP: The maximum precipitation that fell in one hour during the day. If 0.00 is shown it indicates a Trace.
Tpcpn: The total precipitation for the day. T indicates a trace. 0.00 indicates either 0 precipitation fell or that the total for the day is missing.

WxType The type of weather, if any, that occurred. The following abbreviations are used: 

  R Rain
  T Thunderstorm
  F Fog
  L Drizzle
  W Showers
  H Haze
  K Smoke
  Z Freezing
  B Blowing
  S Snow
  I Ice
  A Hail
PDir: The prevailing wind direction in degrees (360 is north, 090 is east, 180 is south, 270 is west) averaged over 36 points of the compass.
AvSp: The average wind speed in miles an hour.
MxS:The maximum wind speed gust or peak wind in miles an hour.
Dir:The direction that occurred with the peak gust.
SkyC:The total sky cover is tenths. 10.0 indicates total cloud cover through the entire day. 0.0 indicates nearly clear. High thin clouds may not be included in the total sky cover for some locations.
MxR:The maximum relative humidity for the day.
MnR:The minimum relative humidity for the day.
AvSLP:The average sea level pressure for the day.

A * to the right of a value indicates it is an extreme for the month.

Near the bottom if each monthly file is a line that starts with "mo". This contains averages or totals of selected daily values through the last day of the month that is available. For instance under the MxT column it is the average maximum temperature from the first of the month (if it is available) through the last day of the month (or the previous day if it is a current month.

A final line may follow the "mo" line and will start with "dp". It is not available for all locations and will not be shown when not available. The "dp" line contains the deparature of data on the "mo" line from normal. It is either the deparature from normal for the entire month, or in cases where the month is not yet complete it is the deparature from normal for the month to date.