Understanding Climate

Cool conditions prevailed across large parts of the North America in 2014. Everywhere else, the frequency of warm days was higher than average, and the frequency of cold nights was below average.

A post for map geeks. How to turn an animation of a year's worth of daily rain maps into a single picture.

The latest installment of NOAA's Arctic Report Card confirms that Arctic air temperatures are rising at more than twice the rate of the planet as a whole. This collection of images highlights some of the key changes in physical and biological conditions in the Far North.

As the assessment now known as the BAMS State of the Climate report pushes into its third decade, international participation is at an all-time high. From atmospheric chemists to tropical meteorologists, more than 420 authors from institutions in 57 countries contributed to this year's report.

Super Typhoon Haiyan slammed into the east coast of Samar and Leyte Islands in the Philippines with what may have been the highest recorded wind speed for a tropical cyclone at landfall. Haiyan, locally known as “Yolanda,” was the deadliest typhoon in the country's modern record.

The annual average concentration of carbon dioxide (CO2) in the atmosphere stood at 395.3 parts per million (ppm) in 2013—a 27 percent increase compared to conditions before the Industrial Revolution. On May 9, 2013, the daily average concentration of CO2 surpassed 400 ppm for the first time at the Mauna Loa Observatory in Hawaii.

While the Northern Hemisphere’s snow cover on land ranked as the 13th most extensive on record in 2013, snow cover extent at the end of the cold season has dropped by 19.9 percent per decade since 1979 relative to the 1981-2010 average.

Large-scale patterns of sea surface salinity in 2013 mirrored the overall trend seen from 2004 to 2013: salty, dry areas are becoming increasingly salty, and fresher areas are becoming increasingly fresh.

Arctic sea ice extent shrunk down to 2.0 million square miles (5.1 million square kilometers) in September 2013—18 percent below the 1981-2010 average, but larger than record low set in 2012.

Globally-averaged surface temperature for 2013 was 0.36 - 0.38° Fahrenheit above the 1981–2010 average, placing it among the top 10 warmest years since record-keeping began.