Farmers and Predicting the Weather

Before meteorologists and the Internet, farmers had to rely on other means to predict the weather.

| April 2015

Red sky at night, sailor’s delight; red sky in morning, sailors take warning.

We’re all familiar with that old saying. It’s just one way folks have attempted to predict the weather, probably since time began. Based on any number of observed patterns of past weather, and not a little superstition and mysticism, some of these indications of future weather are still popular and some are surprisingly accurate.

Farmers everywhere have always had a strong interest in the weather, for obvious reasons. For centuries, a well-thumbed almanac hung on a nail by the door of every farmhouse. Most planting and harvesting decisions were based on information from those books. An annual publication, the almanac contained (and still does) weather forecasts, recommended planting dates, tide tables and other information arranged according to the calendar, including astronomical data and statistics such as times for sunrise and moonset, dates of eclipses and other helpful information.

Instruments of change

During the 1400s, the hygrometer (an instrument to measure humidity) was developed in Germany. A crude anemometer (used to measure wind speed) was invented in Italy in 1450. Galileo invented a gas-filled thermometer at about the turn of the 17th century, but it wasn’t very accurate or reliable. Although he also experimented with alcohol thermometers, it was another 100 years before Daniel Gabriel Fahrenheit developed the much more accurate mercury-filled version. In 1643, an Italian named Evangelista Torricelli invented the barometer to measure atmospheric pressure. The barometer remains an important instrument for weather predicting. These instruments were improved over the next century or two, and when, in the 1830s, the telegraph made swift transmission of the weather trends indicated by these instruments possible, scientists were able to study and track weather systems and issue forecasts.

Two officers of the Royal Navy are generally credited with the beginning of modern weather forecasting. In roughly 1830, Rear Admiral Francis Beaufort developed the wind force scale in use today. In those days of sailing ships, the scale was based upon the effect different wind velocities had on the sails of a frigate. For example, wind scale 0 was for total calm, when no headway could be made using sails, to 12 for a hurricane, “or that which no canvas could withstand.” With the demise of sailing ships, the scale was modified to reflect actual wind speed.

Vice Admiral Robert FitzRoy, who commanded HMS Beagle during Charles Darwin’s famous voyage from December 1831 to October 1836, retired from the Royal Navy in 1851. After that time, he developed a number of improved barometers and had them placed at ports along the coast of England. With the reports wired to him daily from these stations, along with weather charts he had devised, he was able to predict future weather with some accuracy.