The invention of the radar is the result of research work of many physicists from the beginning of the 20th century.
As you can imagine, the weather radar was not born from the last rain.
The first operational radars were generally attributed to the physicist Sir Robert Watson-Watt in 1935. These radars were used primarily for military purposes and were used for aerial surveillance.
It was therefore necessary to detect on a large area possible enemy planes (or friends) using radio waves (electromagnetic waves).
The electromagnetic waves emitted by the radar are in the form of pulses. When these pulses hit targets (in this case here aircraft), they are partly reflected in the form of echoes and return to the radar, which allows to locate these objects spatially. So the word radar is a contraction of Radio Detecting and Ranging .
Obviously, radars were widely used and improved during the Second World War.
During this period, radar operators occasionally noticed strange echoes appearing on the screens, and we even thought we were dealing with aircraft, even squadrons of aircraft. After the war and many studies, it was discovered that these parasitic radar echoes were actually caused by rain or snow.
In Canada, it is mainly the work of J. Stewart Marshall and his team (at McGill University) that made it possible to use this new data for meteorological purposes.
Thus at the end of the war, military radars were used to create a meteorological radar network.
This new meteorological detection tool has significantly improved the short-term forecast.