National Oceanic and Atmospheric Administration data showed the average temperature in June to be 1.22 degrees higher than the historical average, USA Today reported Friday.
"It's part of an overall trend," Jay Lawrimore, climate analysis chief at NOAA's National Climatic Data Center, said. "Global temperatures ... have been rising for the last 100-plus years. Much of the increase is due to increases in greenhouse gases."
If the trend continues, Lawrimore said, flooding rains will become more common.
"The atmosphere is able to hold more water as it warms, and greater water content leads to greater downpours," he said.
Heavy snows, droughts and Arctic ice melts will also increase and become more severe, he said.
Not everyone agrees with the new data and its interpretation.
Marc Morano, editor of the the Climate Depot Web site, says the government "is playing the climate fear card by hyping predictions and cherry-picking data."
Meteorologist Joe D'Aleo disagrees, too. He says oceans are entering a cooling cycle that will lower temperatures, and that
too many of the weather stations NOAA uses are in warmer urban areas.
"The only reliable data set right now is satellite," D'Aleo says.
NASA satellite data show the average temperature in June was 0.43 degrees higher than normal, he says, not the 1.22 degrees given by NOAA.