on Baltimore, Maryland on February 5–6, and a second storm precipitated on February 9–10. In New York City, a separate storm deposited on February 25–26. Another snowstorm swept Catalonia as well as neighbouring French departments (Languedoc-Rousillon, Midi-Pyrenées) on March 8, depositing 60 cm of snow in Girona. This kind of snowstorm activity is considered to be highly anomalous, and as extreme as the negative Arctic oscillation value itself. These negative values of the AO during 2010 and following into the next winter allowed colder air to penetrate much further south than usual into sub-tropical South Florida which brought record breaking low temperatures and months registered in many locations and the coolest average monthly minimum temperatures for February, March and December that year in the tropical beach getaway of Cancún, up to over 4C below the climate period averages. The greatest negative value for the Arctic oscillation since 1950 in January was −3.767 in 1977, which coincided with the coldest mean January temperature in New York City, Washington, D.C., Baltimore, and many other mid-Atlantic locations in that span of time, although the January Arctic oscillation has been negative only 60.6% of the time between 1950 and 2010, nine of the ten coldest Januarys in New York City since 1950 have coincided with negative Arctic oscillations. See also Antarctic oscillation Climate variability and change John Michael Wallace North Atlantic Current Polar amplification Polar vortex Siberian High References External links Overview of Arctic Climate Indices Monthly Northern Hemisphere Annular Mode (NAM) Index or Arctic Oscillation (AO) Index 1850–2013 Daily Northern Hemisphere Annular Mode (NAM) Index or Arctic Oscillation (AO) Index 1948–2013 NOAA 3-month running mean AO Index 1950–2009 Arctic roots of 'upside-down' weather BBC news, Tuesday, 5 January 2010 Regional climate effects Environment of the Arctic Climate oscillations