Hot-pressed α-silicon carbide temperature monitors were irradiated at 525 and 772°C to 4.8 × 1021 n/cm2 (E > 0.18 MeV). Postirradiation isochronal annealing was carried out for 1-h periods at either 25 or 50°C intervals between 300°C and 1200 to 1500°C. Above the irradiation temperature the sample length decreased linearly with annealing temperature, while the electrical resistivity increased exponentially with temperature. Straight lines were fitted through the length-versus-temperature and log (resistivity)-versus-temperature data points and the temperature, T1 at which the line intersected the as-irradiated base line was measured. For both length change and resistivity, mean values of T1 agreed with the measured irradiation temperature within experimental accuracy. The precision of a single determination of T1 was obtained from curve-fitting statistics and was about ±20°C for irradiation at 525°C and ±30 at 772°C (90% confidence limits) for both length and resistivity measurements. The sample-to-sample reproducibility of T1 was estimated from the standard deviation of four repeated measurements and was similar to the precision of a single determination.