WASHINGTON, Sept 10, 2012 (AFP) - The continental United States has recorded its warmest ever year so far with all but one of the 48 states clocking temperatures above the historical average, official data showed Monday. The National Oceanic and Atmospheric Administration said the average temperature from January through August was 14.8 Celsius (58.7 F), beating the 2006 record and 2.2 C (4.0 F) above the 20th century average. Only Washington in the Pacific Northwest had near average temperatures, although the state like much of the country suffered drier than usual conditions, the agency said. The summer as a whole was the third hottest on record. In August, the average temperature in the continental United States was 23.6 C (74.4 F). While above 20th century levels, the month was the 16th warmest August on record -- not as drastic as recent data. The planet has recorded a slew of record temperatures over the past decade. Scientists say that industrial output of carbon dioxide has caused the rising temperatures along with greater frequency of natural disasters.