Weather satellites record images using both visible light and infrared so they can record during the day and at night. They record not only cloud systems but sea surface temperatures and various other data from the atmosphere and the ground. Both GOES and POES satellites also provide data that is not specifically related to the weather. Because they monitor vegetation growth they provide data that is used to forecast locust plagues in Africa. They can track migrating birds and swarms of bats, and can map forest fires.
Radar is an acronym for ra dio d etection a nd r anging.
Radar was simultaneously developed in several countries. It was seen as useful to track icebergs, to prevent ship collisions, and to track plans and ships. It was soon discovered that the radio waves not only bounced off such solid objects but also echoed back from such elemental events as rain storms. The answer to this question refers back to ancient Greece where a meteor was any atmospheric penomenon that might appear in the sky. This of course included clouds, rain, rainbows etc.