The Global Hourly Summaries are simple indicators of observational normals which include climatic data summarizations and frequency distributions. These typically are statistical analyses of station data over 5-, 10-, 20-, 30-year or longer time periods. In a GIS map service, the results of these calculations are represented by a given symbology set for different statistical criteria and observation type. Having the ability to modify the symbology "on-the-fly" is a useful tool in the analysis of station trends, accuracy, and regional or localized variances. The summaries are computed from the global surface hourly dataset. This dataset totaling over 350 gigabytes is comprised of 40 different types of weather observations with 20,000 stations worldwide. NCDC and the U.S. Navy have developed these value added products in the form of hourly summaries from many of these observations. These data are a subset of the Integrated Surface Hourly dataset (DSI-3505) (C00532).

Global Surface Summary of the Day is derived from The Integrated Surface Hourly (ISH) dataset. The ISH dataset includes global data obtained from the USAF Climatology Center, located in the Federal Climate Complex with NCDC. The latest daily summary data are normally available 1-2 days after the date-time of the observations used in the daily summaries. The online data files begin with 1929 and are at the time of this writing at the Version 8 software level. Over 9000 stations' data are typically available. The daily elements included in the dataset (as available from each station) are: Mean temperature (.1 Fahrenheit) Mean dew point (.1 Fahrenheit) Mean sea level pressure (.1 mb) Mean station pressure (.1 mb) Mean visibility (.1 miles) Mean wind speed (.1 knots) Maximum sustained wind speed (.1 knots) Maximum wind gust (.1 knots) Maximum temperature (.1 Fahrenheit) Minimum temperature (.1 Fahrenheit) Precipitation amount (.01 inches) Snow depth (.1 inches) Indicator for occurrence of: Fog, Rain or Drizzle, Snow or Ice Pellets, Hail, Thunder, Tornado/Funnel Cloud Global summary of day data for 18 surface meteorological elements are derived from the synoptic/hourly observations contained in USAF DATSAV3 Surface data and Federal Climate Complex Integrated Surface Hourly (ISH). Historical data are generally available for 1929 to the present, with data from 1973 to the present being the most complete. For some periods, one or more countries' data may not be available due to data restrictions or communications problems. In deriving the summary of day data, a minimum of 4 observations for the day must be present (allows for stations which report 4 synoptic observations/day). Since the data are converted to constant units (e.g, knots), slight rounding error from the originally reported values may occur (e.g, 9.9 instead of 10.0). The mean daily values described below are based on the hours of operation for the station. For some stations/countries, the visibility will sometimes 'cluster' around a value (such as 10 miles) due to the practice of not reporting visibilities greater than certain distances. The daily extremes and totals--maximum wind gust, precipitation amount, and snow depth--will only appear if the station reports the data sufficiently to provide a valid value. Therefore, these three elements will appear less frequently than other values. Also, these elements are derived from the stations' reports during the day, and may comprise a 24-hour period which includes a portion of the previous day. The data are reported and summarized based on Greenwich Mean Time (GMT, 0000Z - 2359Z) since the original synoptic/hourly data are reported and based on GMT.

Local Climatological Data (LCD) contains summaries from major airport weather stations that include a daily account of temperature extremes, degree days, precipitation amounts and winds. Also included are the hourly precipitation amounts and abbreviated 3-hourly weather observations. This is the final quality controlled copy and generally has a one to two month time lag. The local climatological data annual file is produced from the National Weather Service (NWS) first and second order stations. These data are contained in the LCD monthly and annual publications. The monthly summaries include maximum, minimum, and average temperature, temperature departure from normal, dew point temperature, average station pressure, ceiling, visibility, weather type, wet bulb temperature, relative humidity, degree days (heating and cooling), daily precipitation, average wind speed, fastest wind speed/direction, sky cover, and occurrences of sunshine, snowfall and snow depth. The annual summary with comparative data contains monthly and annual averages of the above basic climatological data in the meteorological data for the current year section, a table of the normals, means, and extremes of these same data, and sequential table of monthly and annual values of average temperature, total precipitation, total snowfall, and total degree days. Also included is a station location table showing in detail a history of, and relative information about, changes in the locations and exposure of instruments. The NCDC also archives a Preliminary Local Climatological Data manuscript that contains similar information, but is not quality controlled.

**Please note, this dataset has been superseded by a newer version (see below). Users should not use this version except in rare cases (e.g., when reproducing previous studies that used this version).** The Global Historical Climatology Network (GHCN) Version 1 is a comprehensive, global, surface, baseline, climate data set designed for monitoring and detecting climate change. Comprised of surface station observations of temperature, precipitation, and pressure, all GHCN data are monthly. GHCN was produced jointly by the NCDC, Arizona State University, and the Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL). GHCN version 1 was released in August of 1992 and has data from ~6,000 Temperature stations ~7,500 Precipitation stations ~2,000 Pressure stations The earliest station data was from 1697. The most recent is from 1990. Version 1 was created from 15 source data sets. Quality Control includes visual inspection of graphs of all station time series, tests for precipitation digitized 6 months out of phase, tests for different stations having identical data, and other tests.

**Please note, this dataset has been superseded by a newer version (see below). Users should not use this version except in rare cases (e.g., when reproducing previous studies that used this version).** The Global Historical Climatology Network (GHCN) Version 1 is a comprehensive, global, surface, baseline, climate data set designed for monitoring and detecting climate change. Comprised of surface station observations of temperature, precipitation, and pressure, all GHCN data are monthly. GHCN was produced jointly by the NCDC, Arizona State University, and the Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL). GHCN version 1 was released in August of 1992 and has data from ~6,000 Temperature stations ~7,500 Precipitation stations ~2,000 Pressure stations The earliest station data was from 1697. The most recent is from 1990. Version 1 was created from 15 source data sets. Quality Control includes visual inspection of graphs of all station time series, tests for precipitation digitized 6 months out of phase, tests for different stations having identical data, and other tests.

Monthly Summaries of Global Historical Climatology Network (GHCN)-Daily is a dataset derived from GHCN-Daily. The data are produced by computing simple averages or monthly accumulations of the daily observations. The meteorological elements calculated for the data set include, but are not limited to: monthly maximum and minimum temperature, monthly precipitation (i.e., rainfall and snow water equivalent), snowfall and snow depth. Users of these monthly summaries have access to simple meteorological summaries for tens of thousands of stations worldwide.

Monthly Summaries of Global Historical Climatology Network (GHCN)-Daily is a dataset derived from GHCN-Daily. The data are produced by computing simple averages or monthly accumulations of the daily observations. The meteorological elements calculated for the data set include, but are not limited to: monthly maximum and minimum temperature, monthly precipitation (i.e., rainfall and snow water equivalent), snowfall and snow depth. Users of these monthly summaries have access to simple meteorological summaries for tens of thousands of stations worldwide.

U.S. National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) numerical weather prediction model 8-day, 3-hourly forecast for the globe at approximately 50-km or 0.5-deg resolution.

National Weather Service (NWS) Station Information System (SIS) contains observing station metadata from November 2016 to present. These are renditions are used for daily updates to the Historical Observing Metadata Repository (HOMR). Within this dataset there are embedded PDFs which are loaded into Environmental Document Access and Display System (EDADS) Version 2 (EV2) in the Cooperative Station History library and the JSON formatted machine readable version of the information on the PDFs which are integrated into HOMR. The station updates contain station profile information, and changes in location, instrumentation, obstructions, observers, and observation times. NCEI only receives these files when something is changed on the station, or every 3 years for a NWS-mandated update. Version 2 of this dataset includes new equipment hierarchy and minor changes to how observer information is structured in the JSON interface files.