PHILADELPHIA _ Temperatures in the contiguous United States were 2.2 degrees below 20th-century averages last month, making it the coldest April in 20 years, according to the government analysis released Tuesday.
Nationally, it was the 13 coldest April, with Iowa and Wisconsin registering their frostiest on record.
Generally, overnight minimum temperatures have been creeping upward in recent decades; however, in April it was the overnight lows driving the departures, NCEI said.
April also was particularly generous with snowfall. The calculated monthly snow-cover was the fifth-largest in the 52-year data set, according to the Rutgers University Snow Lab.
The center won't be releasing its global surface-temperature report until later in the month _ that analysis is far more complicated.
The NASA/University of Alabama satellite data posted last week had the planetary temperature holding fairly steady in the first four months of the year but still above the 30-year normal.
While the global temperature tends to change ponderously month-to-month, the distribution of heat and cold often changes radically.
North American was favored for the chill in April, according to the satellite analysis.
Meanwhile, an area over the Arctic Ocean, northeast of Russia's Lyakhovsky Islands, temperatures were close to 10 degrees above normal.
