I am looking for a good wireless thermometer.  We heat a small room inside of a non insulated shed with two space heaters.  We store liquid fertilizer in this room.  We have gone through four or five in the last four years.  The problem is that the screen that reads out the temp is sitting out in the cold and it is almost impossible to read it.  I am looking for ideas.  I have searched and searched for long range thermometers but most of them stop around 300 feet.  The next closest building is probably 500 - 600 feet.  No WiFi around.  Any one got any ideas?  This room is in a 40 x 70 building that has a 40 x 40 secondary containment  inside of it.  The room is probably 12 x24 or so with two 5,000 gallon tanks inside it.