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.
February 2016 Blended Land and Sea Surface. Temperature Percentiles. The combined average temperature over global land and ocean surfaces for February 2016 was the highest for February in the 137-year period of record, at 1.21Â°C (2.18Â°F) above the 20th century average of 12.1Â°C (53.9Â°F).