My 5-in-1 is screwed to the railing on my deck, about 45' from the consoles. The signal passes through two external walls and an interior wall. (House was extended, and old exterior wall is now an interior wall.) I'm reading full bars signal strength at the console.
Try putting batteries into the 5-in-1 and just laying it on your roof to see how far the signal gets inside your house. I think you'll be surprised at how far the signal actually travels.
Before discovering AcuRite, my only experiences with wireless thermometers was that I had to hang the receiver on the window frame and the transmitter less than 5' away outside to get a signal through. I have an AcuRite thermometer using the same radios as the 5-in-1, with the transmitter probe out in my detached garage and the receiver set on an end table in the living room. The signal needs to pass through the garage wall, 30 feet of yard, two exterior walls, and two interior walls...and it still gets 3 bars! Like I said, try a few different locations with the 5-in-1 before you pull the rain gauge stopper strip out, because wireless range probably won't be a problem wherever you decide to site the outdoor sensor.....