Did You Know?
NOAA's National Centers for Environmental Information (NCEI) is the world's largest active archive of weather data. It houses data archives dating back to 1880 from all over the world. Each month, countries from all over the world send their land-based meteorological surface observations, meaning temperature and precipitation measurements, to NCEI to be added to the global record. This information is sent through the World Meteorological Organization's (WMO) Global Telecommunication System (GTS)—a coordinated system for the rapid collection, exchange and distribution of observation data from more than 200 countries around the world. The data are sent in a format called "CLIMAT messages", which are a summary of monthly weather data for a specific station. The CLIMAT message contains information of average pressure at station level, average air temperature, maximum air temperature, minimum air temperature, average vapor pressure, total precipitation, and total sunshine for a particular month. These messages are typically sent to NCEI by the 8th of every month. NCEI uses the data to produce numerous climate publications, such as the Monthly Global Report. The red dots on the loop above show how a typical month's worth of data arrives at NCEI, in a day-by-day, country-by-country fashion. Please refer to the WMO for detailed information about CLIMAT messages or the GTS.