Louisiana - Geography - Climate

Climate

Louisiana has a humid subtropical climate (Köppen climate classification Cfa), perhaps the most "classic" example of a humid subtropical climate of all the Southcentral states, with long, hot, humid summers and short, mild winters. The subtropical characteristics of the state are due in large part to the influence of the Gulf of Mexico, which even at its farthest point is no more than 200 miles (320 km) away. Precipitation is frequent throughout the year, although the summer is slightly wetter than the rest of the year. There is a dip in precipitation in October. Southern Louisiana receives far more copious rainfall, especially during the winter months. Summers in Louisiana are hot and humid, with high temperatures from mid-June to mid-September averaging 90 °F (32 °C) or more and overnight lows averaging above 70 °F (22 °C). In the summer, the extreme maximum temperature is much warmer in the north than in the south, with temperatures near the Gulf of Mexico occasionally reaching 100 °F (38 °C), although temperatures above 95 °F (35 °C) are commonplace. In northern Louisiana, the temperatures reach above 105 °F (41 °C) in the summer.

Temperatures are generally mildly warm in the winter in the southern part of the state, with highs around New Orleans, Baton Rouge, the rest of south Louisiana, and the Gulf of Mexico averaging 66 °F (19 °C), while the northern part of the state is mildly cool in the winter with highs averaging 59 °F (15 °C). The overnight lows in the winter average well above freezing throughout the state, with 46 °F (8 °C) the average near the Gulf and an average low of 37 °F (3 °C) in the winter in the northern part of the state. Louisiana does have its share of cold fronts, which frequently drop the temperatures below 20 °F (−8 °C) in the northern part of the state, but almost never do so in the southern part of the state. Snow is not very common near the Gulf of Mexico, although those in the northern parts of the state can expect one to three snowfalls per year, with the frequency increasing northwards. Louisiana's highest recorded temperature is 114 °F (46 °C) in Plain Dealing on August 10, 1936 while the coldest recorded temperature is −16 °F (−27 °C) at Minden on February 13, 1899.

Louisiana is often affected by tropical cyclones and is very vulnerable to strikes by major hurricanes, particularly the lowlands around and in the New Orleans area. The unique geography of the region with the many bayous, marshes and inlets can make major hurricanes especially destructive. The area is also prone to frequent thunderstorms, especially in the summer. The entire state averages over 60 days of thunderstorms a year, more than any other state except Florida. Louisiana averages 27 tornadoes annually, some in part in 2010. The entire state is vulnerable to a tornado strike, with the extreme southern portion of the state slightly less so than the rest of the state. Tornadoes are much more common from January to March in the southern part of the state, and from February through March in the northern part of the state.