Room temperature does not have an exact scientific definition. It means a temperature that is normal in rooms used by human beings.
Human comfort and health [change]
A comfortable room temperature depends on individual needs and other factors. According to the West Midlands Public Health Observatory (UK), 21 °C (70 °F) is the recommended living room temperature, and 18 °C (64.4 °F) is a good bedroom temperature.
However, this might not be true for countries found near the equator. As the temperature is higher, the room temperature is around 30°C (86 °F).
Room Temperature is the temperature that is comfortable and normal to be in.
For scientific work, room temperature is taken to be about 20 to 25 degrees Celsius with an average of 23°C (about 73.4 degrees Fahrenheit (°F), 528 to 537 degrees Rankine (°R), or 293 to 298 Kelvins (K)). For numerical convenience, either 20 °C or 300 K is often used.
Condition for physical experiments [change]
The progress and results of many scientific and industrial processes can sometimes depend on the temperature of the surroundings of the equipment. For example, a measurement of the charge of the electron does not depend upon the temperature of the test equipment. In this case, if scientists mention temperature at all, they usually only mention "room temperature", which means that what is being measured has not been cooled or heated.
- Why more people die in the winter, by Michelle Roberts, Health reporter, BBC News 
- The American Heritage® Dictionary of the English Language, Fourth Edition.