Please see adjacent questions about what means ambient and room temperatures. Here we will explain more what means ±0.5°C accuracy. The accuracy of ±0.5°C means that if you take two sensor and place them both along with each other (no space between) in the environment of, say, 0.5°C the one may show you 0°C (0.5-0.5) and another 1°C (0.5+0.5). So you have 1°C difference or 1.8F (F=9*C/5). If you now place them in a few inches (centimeters) from each other, say 5" or 10 cm you may have different temperatures, because of multiple factors as the temperature in the point 'A' and the point 'B' in 5" (10 cm) is already different and thus you may have, say, 2C difference easy, where 2C means 3.6F. If you want to compare our sensor with some other sensor you would be better to do this when both are set in Celsius, but this comparison make little sense as there is no such terms like "the correct temperature" exists in general. We may bias values you see from the sensor - to make a so called calibration - for you if you tell us what difference you would like to see. This should be done in Celsius.