The normal body temperature for a dog falls within the range of 100°F to 102.5°F (about 38°C to 39.2°C). If your dog's temperature is outside of this range, you should contact your veterinarian.Body temperature over 104°F or under 99°F indicates an emergency situation.In general, the most accurate way to measure a dog's body temperature is rectally.However, some ear thermometers made especially for dog's ears can be considered somewhat accurate. In a pinch, temperature can be measured in the axillary region (underarm) and one degree can be added to the final reading.n general, the most accurate way to measure a dog's body temperature is rectally. However, some ear thermometers made especially for dog's ears can be considered somewhat accurate. In a pinch, temperature can be measured in the axillary region (underarm) and one degree can be added to the final reading.