This collection contains records from the US Weather Bureau between 1912 and 1941, and center around the Yorba Linda weather
observation station. The strength of this collection lies in the annual weather reports conducted by 'Cooperative Observers',
which shed light on how meteorological data was gathered in the early twentieth century.
The Weather Bureau (now the National Weather Service) was created under the Organic Act in 1890 and the COOP program was soon
transferred into their responsibility. By then, the number of weather observers had grown to around 2,000 stations. However,
it wasn't until 1953 that the push was made to expand the network across the country. Dr. Helmut Landsberg conducted a study
with Iowa State University and came to the conclusion that an observation site was needed every 25 miles. This is the system
that the National Weather Service uses today. By 1990, the number of observers had grown to 10,000 stations, and today there
are over 12,000 COOP stations.
Source: National Weather Service (weather.gov)