June 2015’s Global Average Temperature Highest in 136 Year Record, Breaking Previous Record High Temperature Record of June 2014
The combined average temperature over global land and ocean surfaces for June 2015 was the highest for June in the 136-year period of record, at 0.88°C (1.58°F) above the 20th century average of 15.5°C (59.9°F), surpassing the previous record set just one year ago by 0.12°C (0.22°F). This was also the fourth highest monthly departure from average for any month on record. The two highest monthly departures from average occurred earlier this year in February and March, both at 0.90°C (1.62°F) above the 20th century average for their respective months, while January 2007 had the third highest, at 0.89°C (1.60°F) above its monthly average.
June 2015 also marks the fourth month this year that has broken its monthly temperature record, along with February, March, and May. The other months of 2015 were not far behind: January was second warmest for its respective month and April was third warmest. These six warm months combined with the previous six months (four of which were also record warm) to make the period July 2014–June 2015 the warmest 12-month period in the 136-year period of record, surpassing the previous record set just last month (June 2014–May 2015). As shown in the table below, the 10 warmest 12-month periods have all been marked in the past 10 months.
This report follows earlier reports that last year global average temperatures were also the highest since the U.S. National Weather Service began recording temperature data on the planet.
Dew point temperature, which is the temperature of the air when the air is holding the maximum amount of water vapor it can hold, is used commonly by weather forecasters as a measure of how humid the air around us will “feel”. Humans are sensitive to changes in humidity in the air because our skin uses the air around us to get rid of moisture in the form of sweat; the evaporation of water uses heat energy thus ridding of the perspiration creates a cooling effect on the skin. If the relative humidity is very high, the air is already saturated with water vapor (at the dew point temperature) and the perspiration won’t evaporate. When this happens, we feel hotter than the actual temperature.
Dew point temperatures throughout the Midwest over the last century climbed steadily, according to a report by Jesse H. Wartman reported higher dew point temperatures (the maximum amount of water vapor (another greenhouse gas) that the air at any one place can hold) “I analyzed dew-point temperatures from the U.S. Upper Midwest over the period 1961-2005. Results show a significant increase in the past 44 years in the cities of Sioux Falls, Minneapolis, Omaha, Des Moines, Kansas City and St. Louis. The tendencies are apparent in monthly, seasonal and yearly averaged trends. Not only were the dew-point temperatures observed to be increasing, the number of extremely high dew points per year was observed to be increasing as well.”