I installed a La Crosse weather station that is 3.75" x 5.5" x 0.5" in size and has a remote sending unit that is 5" x 1.5" x 0.75" in size. Works well though I remove the batteries when not using the camper. 
I like it to know the outside temperatures and have an idea as to whether or not I need to worry about freezing in the water line. I had that problem a year ago in Yellowstone and it was good to know exactly how cold it got outside exactly where we were camped. 
Weather radios have their place but most of the time we cannot get a signal we are and fall back to the internet for a forecast for the days ahead at our planned destinations. Neither is any good at telling me how cold it got the night before or even what the current outside temperature is in the morning. 
They also have a barometer history function which helps to spot a coming front and change in the weather. I would have loved to have had this on sailboats when I was making ocean passages as barographs were too large and much too expensive to even consider.