The invention of the thermometer and the barometer during the Scientific Revolution allowed for systematic recordkeeping, that began as early as 1640 in England.[3] Early climate researchers include Edmund Halley, who published a map of the trade winds in 1686 after a voyage to the southern hemisphere. Benjamin Franklin (1706–1790) first mapped the course of the Gulf Stream for use in sending mail from the United States to Europe. Francis Galton (1822–1911) invented the term anticyclone.[5] Helmut Landsberg (1906–1985) fostered the use of statistical analysis in climatology, which led to its evolution into a physical science.
In the early 20th century, climatology was mostly focused on the description of regional climates. This descriptive climatology was mainly an applied science, giving farmers and other interested people statistics about what the normal weather was and how big chances were of extreme events.[6] To do this, climatologists had to define a climate normal, or an average of weather and weather extremes over a period of typically 30 years.[7]