Wash the thermometer in soap and rinse with cool, clean water before and after you use it. Do not use hot water because the thermometer may break. After washing, it is best to soak the thermometer in alcohol for 20 minutes. You can use ethyl, isopropyl, or medical alcohol (ethanol).
1 In 2015, the average temperature across global land and ocean surfaces was 1.62Â°F (0.90Â°C) above the twentieth-century averageâthe hottest year in the 136-year record.  Since 1976, every year has been warrmer than the long-term average.
The world has mainly grown hotter since 1980, at a rate of nearly 0.2 Â°C (0.36 Â°F) per decade. The annual global temperature from 2000 to 2009 was 0.61 Â°C (1.1 Â°F) higher than the average temperature for 1951 to 1980. If the current rate of increase continues, the world will warm by 2 Â°C (3.6 Â°F) in the next century.