Cooling neutron stars have temperatures of order 1 million kelvins and so thermally emit at X-ray wavelengths. Measurement of an x-ray spectrum allows the temperature to be determined, assuming it is thermal emission from the surface of a neutron star. The resulting temperature for RRAT J1819-1458 is much cooler than that found on the surface of magnetars, and suggests that despite some shared properties between RRATs and magnetars, they belong to different populations of neutron stars. None of the other pulsars identified as RRATs has yet been detected in X-ray observation. This is in fact the only detection of these sources outside of the radio band.