LCD Dataset Documentation.docx
Local Climatological Data (LCD) Dataset Documentation
The Local Climatological Data (LCD) summaries provide a synopsis of climatic values for a single weather
station over a specific month. The summaries are a product of surface observations from both manual and
automated (AWOS, ASOS) stations with source data taken from the National Centers for Environmental
Information’s Integrated Surface Data (ISD) dataset. Geographic availability includes thousands of locations
worldwide. Climatic values given include hourly, daily, and monthly measurements of temperature, dew point,
humidity, winds, sky condition, weather type, atmospheric pressure and more.
General conventions: Times are in Local Standard Time (LST) unless otherwise noted. Temperatures are
given in whole degrees F and tenths of degrees C (as noted below). Wind speeds are in miles per hour, with
wind direction given using a 360 degree compass indicating the direction from which the wind was blowing
with respect to true north (e.g. 360 = winds blowing from true north, 180 = south, etc.). Precipitation amounts
are given in inches, usually to the nearest hundredth, unless otherwise noted. Trace amounts of precipitation are
indicated with a “T.” Departures from normal are given for some elements using XXXXXXXXXXas the standard for
normal. Further information concerning these generalities and units of measure are given where needed for each
section below.
Table of Contents:
Daily Summary/Monthly Summary
Hourly Observations
Hourly Remarks
Hourly Precipitation Table
CSV and ASCII Data Files
Present Weather Appendix
Daily Summary/Monthly Summary:
Daily Summary:
The month and year as well as the station information (location, latitude, longitude, elevation) are included in
the heading at the top of the table. A description of the daily data values follows:
Date: Date (day of month given in two digits) Note: Month and year are given in the heading.
Temperature - Max: Maximum temperature for the day (in whole degrees Fahrenheit). An asterisk (*) is used
to designate when a daily maximum temperature is also the extreme maximum for the month.
Temperature - Min: Minimum temperature for the day (in whole degrees Fahrenheit). An asterisk (*) is used
to designate when a daily minimum temperature is also the extreme minimum for the month.
Temperature - Avg: Average temperature for the day (in whole degrees Fahrenheit). This is based on the
arithmetic average of the maximum and minimum temperature for the day.
Temperature - Dep: Average temperature’s departure from XXXXXXXXXXnormal temperature (in whole
Fahrenheit degrees using “-” to indicate below normal)
Temperature - ARH: Average daily relative humidity (in whole percent)
Temperature - ADP: Average daily dew point temperature (in whole degrees Fahrenheit)
Temperature - AWB: Average daily wet-bulb temperature (in whole degrees Fahrenheit)
Degree Days - Heat: Heating degree days (in whole degrees using a 65 degree F base)
Degree Days - Cool: Cooling degree days (in whole degrees using a 65 degree F base)
Sun - Rise: Time of sunrise using a 24-hour clock (Local Standard Time – Daylight Savings Time is not used)
Sun - Set: Time of sunset using a 24-hour clock (Local Standard Time – Daylight Savings Time is not used)
Weather (WT**): Daily occu
ences of weather types. The 2-digit number in each designation co
esponds to
the WT (weather type code) used in GHCN-Daily dataset. For example WT01 in GHCN-Daily is represented as
FG:01 (fog) in the LCD. Contractions used are given below.
FG:01 (WT01) - Fog, ice fog, or freezing fog (may include heavy fog)
FG+:02 (WT02) - Heavy fog or heavy freezing fog (not always distinguished from fog)
TS:03 (WT03) - Thunder
PL:04 (WT04) - Ice pellets, sleet, snow pellets or small hail
GR:05 (WT05) - Hail (may include small hail)
GL:06 (WT06) - Glaze or rime
DU:07 (WT07) - Dust, volcanic ash, blowing dust, blowing sand or blowing obstruction
HZ:08 (WT08) - Smoke or haze
BLSN:09 (WT09) - Blowing or drifting snow
FC:10 (WT10) - Tornado, water spout or funnel cloud
WIND:11 (WT11) - High or damaging winds
BLPY:12 (WT12) - Blowing spray
BR:13 (WT13) - Mist
DZ:14 (WT14) - Drizzle
FZDZ:15 (WT15) - Freezing drizzle
RA:16 (WT16) - Rain
FZRA:17 (WT17) - Freezing rain
SN:18 (WT18) - Snow, snow pellets, snow grains or ice crystals
UP:19 (WT19) - Unknown precipitation
MIFG:21 (WT21) - Ground fog
FZFG:22 (WT22) - Ice fog or freezing fog
Precipitation - Total Liquid Content (TLC): Water equivalent amount of precipitation for the day (in inches
to hundredths). This is all types of precipitation (melted and frozen). T indicates trace amount of precipitation.
If left blank, precipitation amount is unreported.
Precipitation - Snowfall: Daily amount of snowfall (in inches to the tenths). T indicates trace amount.
Precipitation - Snow Depth: Daily reading of snow on ground (in whole inches). T indicates trace amount.
Pressure - Avg Stn: Daily average station pressure (in inches of mercury, to hundredths)
Pressure - Avg SL: Daily average sea level pressure (in inches of mercury, to hundredths)
Wind - Avg Spd: Daily average wind speed in miles per hour miles per hour, to tenths)
Maximum Wind Speed - Peak Speed: peak wind speed for the day (in whole miles per hour)
Maximum Wind Speed - Peak Dir: direction of wind during peak wind speed for the day given as direction
from which wind was blowing using a 360 degree compass with respect to true north (e.g north = 360, south =
180, etc.)
Maximum Wind Speed - Sust. Speed: maximum sustained wind speed for the day (in whole miles per hour).
Note: For U.S. locations this is the fastest reported speed for the day that is sustained for at least 2 minutes for
years 1994 and later. For earlier years it is the fastest reported speed sustained for at least 1 minute.
Maximum Wind Speed - Sust. Dir): direction of wind during maximum sustained wind speed for the day
given as direction from which wind was blowing using a 360 degree compass with respect to true north
Monthly Summary:
The bottom section of the Daily Summary form includes information such as monthly maximum, minimum and
mean temperatures, average dew point, wet-bulb and relative humidity, monthly total heating and cooling
degree days, precipitation and snowfall totals, etc. Departures from normal (using XXXXXXXXXXnormals) are also
included for both temperature, precipitation as well as a tally of the number of days selected temperature
thresholds (max temperature >=90
=32, min <=32
=0) and precipitation thresholds (>=0.01 and >=0.10)
were reached, number of snowfall days > = 1 inch, number of days thunderstorms or heavy fog are reported,
etc. The month’s greatest amount of precipitation to fall in 24 hours is also given (amount and date) as well as
the 24 hour greatest snowfall (amount and date) and highest snow depth (height and date). Monthly and season-
to-date totals are computed for heating and cooling degree day data and departures from XXXXXXXXXXnormal are
also given with these. The extreme highest and lowest sea -level pressures recorded and the dates they occu
ed
are also given. Units used are consistent with what appears in the upper part of the table (described above).
These data originate from the Integrated Surface Data (ISD). More very technical details regarding these
observations can be found in the ISD documentation located at www1.ncdc.noaa.gov/pu
data/ish/ish-format-
document.pdf .
Hourly Observations:
The month and year as well as the station information (location, latitude, longitude, elevation) are included in
the heading at the top of the table. A description of the data values follows:
Date: Date (day of month given in two digits) Note: Month and year are given in the heading.
http:
www1.ncdc.noaa.gov/pu
data/ish/ish-format-document.pdf
http:
www1.ncdc.noaa.gov/pu
data/ish/ish-format-document.pdf
Time: Time of observation given as a 4-digit number using a 24-hour clock in local standard time (e.g. 1751 =
5:51 pm LST). No adjustments are made to account for Daylight Savings Time (DST).
Station Type: Code showing source or combination of sources used in creating the observation. Decoding
information for this is found in Integrated Surface Data documentation (www1.ncdc.noaa.gov/pu
data/ish/ish-
format-document.pdf) in Control Data Section position 28.
Sky Conditions: A report of each cloud layer (up to 3) giving the following information.
Each layer given in the following format: ccc:ll-xxx where:
1) ccc is Coverage: CLR (clear sky), FEW (few clouds), SCT (scattered clouds), BKN (
oken clouds), OVC
(overcast), VV (obscured sky), 10 (partially obscured sky).
2) ll is Layer amount used in conjunction with coverage code above. Given in eighths (aka “oktas”) of sky
covered by cloud. Specifically 00-08 indicates the number of oktas that cloud layer takes up in the total sky. 00
co
esponds to CLR, 01-02 co
esponds to FEW, 03-04 co
esponds to SCT, 05-07 co
esponds to BKN and 08
co
esponds to OVC. 09 indicates an obscuration (i.e. the sky cannot be seen due to obscuring phenomena - e.g.
due to smoke, fog, etc.). 10 indicates a portion of the sky is obscured (i.e. partial obscuration). For additional
information see Integrated Surface Data documentation. (http:
www1.ncdc.noaa.gov/pu
data/ish/ish-format-
document.pdf) in Cloud and Solar Data portion of Additional Data Section.
3) xxx is the Cloud base height at lowest point of layer. In the case of an obscuration this value represents the
vertical visibility from the point of observation. Given in hundreds of feet (e.g. 50 = 5000 ft, 120 = 12000 feet).
In some cases a cloud base height will be given without the co
esponding cloud amount. In these case the cloud
amount is missing or not reported.
Up to 3 layers can be reported however by definition when clear skies are reported it will be reported as only
one layer as CLR-00. Obscurations will be reported as VV-xx where xx is the vertical visibility into the
obscuring phenomena.
Additional information about cloud cover data: