Climate of Georgia (U.S. state)

The climate of Georgia is a humid subtropical climate, with most of the state having short, mild winters and long, hot summers. The Atlantic Ocean on the east coast of Georgia and the hill country in the north impact the state's climate.^[1] Also, the Chattahoochee River divides Georgia into separate climatic regions with the mountain region to the northwest being cooler than the rest of the state; the average temperatures for the mountain region in January and July are 39 °F (4 °C) and 78 °F (26 °C) respectively.^[2] Winter in Georgia is characterized by mild temperatures and little snowfall around the state, with the potential for snow and ice increasing in the northern parts of the state. Summer daytime temperatures in Georgia often exceed 95 °F (35 °C). The state experiences widespread precipitation. Tornadoes and tropical cyclones are common.

Most of Georgia has a sub-tropical climate, with hot and humid summers, except at the highest elevations. Weather conditions in various localities of Georgia depend on how close they are to the Atlantic Ocean or Gulf of Mexico, and their altitude. This is especially true in the mountainous areas in the northern part of the state, which are farther away from ocean waters and can be up to 4,500 feet (1,400 m) or higher above sea level. The areas near the Florida-Georgia border, extending from the Atlantic Ocean westward to the Chattahoochee River, experience the most subtropical weather, similar to that of Florida: hot, humid summers with frequent afternoon thunderstorms and mild, somewhat drier winters. The USDA Hardiness Zones for Georgia range from Zone 7A (0 °F to 5 °F) in the mountains to Zone 9B (25 °F to 30 °F) along portions of the coast.^[3]

Despite having moderate weather compared to many other states, Georgia has occasional extreme weather. The highest temperature ever recorded is 112 °F (44 °C),^[4] while the lowest ever recorded is −17 °F (−27 °C).^[5] Heat waves with temperatures over 100 °F (38 °C) have often been recorded.

The entire state, including the North Georgia mountains, receives moderate to heavy rain, which varies from 45 inches (1,100 mm) in central Georgia^[6] to approximately 75 inches (1,900 mm) around the Northeast part of the state.^[7] Georgia has had severe droughts in the past, especially in 2007. Tropical Storm Alberto in July 1994 looped across central Georgia, leading to 24-hour rainfall amounts exceeding 20 inches (510 mm) across central sections of the state.^[8] It also became the wettest tropical cyclone on record for the state of Georgia, eclipsing the record set in 1929.^[9] Snowfall, which occurs in most winters, increases in frequency and average amounts per year to the north.

Southern and southeast areas of the state experience snow much less frequently than other parts of Georgia. The Georgia Piedmont, sometimes referred to as the Blue Ridge province,^[10] is somewhat cooler in winter than the coastal areas. The Southern areas of Piedmont may receive snow every other year, while areas close to the foothills get snow a couple of times a year averaging anywhere from a trace up 2" of annual snowfall. The biggest winter threat to the northern piedmont is freezing rain which is rain that freezes on contact. The mountains of Georgia have the coolest climate and most frequent snowfall in the state, although snowfall is less than any other part of the Appalachian Mountains. The exception to this is the mountain counties of Fannin, Gilmer, Pickens, Union, White and Rabun. The mountains can average between 4 and 18 inches annually. Surrounding counties typically average 3 to 8 inches of snow annually. Elevations over 4,000 feet can have particularly brutal winters with some storms blanketing the mountains with over a foot of snow.^[11] The mountains above 3,500 feet or parts of the Appalachian trail average 10-25 inches of snow in one season. The highest mountain in Georgia, Brasstown Bald, averages 30–40 inches of snow per season. Heavy snow in the extreme northern counties is considered 5 inches (13 cm) or more of snow in a 12-hour period or 7 inches (18 cm) or more of snow in a 24-hour period". Watches for heavy snow are issued when a 50 percent or greater chance of 2 inches (5.1 cm) or more of snow falling in a 12-hour period, or 4 inches (10 cm) or more in a 24-hour period is expected.^[12][13]

Winter weather watches are issued when there is a "50 percent or greater chance of significant and damaging accumulations of ice during freezing rain situations"; these watches are normally issued 12 to 48 hours in advance. A winter storm warning for an ice storm means that icy conditions are "occurring, imminent, or have a very high probability of occurring". These warnings are usually issued when there is an 80 percent or greater chance of meeting ice storm conditions.^[14]

Blizzards in Georgia are rare. The last blizzard the state had was in March 1993.^[15][16]

Winter in southern Georgia, which lasts from December to January, are much more mild. Daytime highs range from approximately 50 °F (10 °C) in the northernmost interior areas to near 70 °F (21 °C) along the coast and in the extreme south.^[17]

Winters in Georgia are determined by the Pacific Ocean. During El Niño, the jet stream is located along the Southern U.S., allowing for colder and wetter conditions with greater snowfall. The opposite phase, La Niña, keeps the jet stream farther north, thus winters are warmer and drier across Georgia.

Weather during springtime in North Georgia and the mountains changes from day to day and year to year.^[18] Early spring in the North Georgia Mountains can be very chilly during the day; average highs are near 62 °F (17 °C). The weather can be highly variable with temperatures ranging between 75 °F (24 °C) and 40 °F (4 °C). The rainiest time of the year is normally April, which can also be a windy month where daytime temperatures can rise to near 75 °F (24 °C) and evening temperatures fall to around 40 °F (4 °C).

Summers are hot and humid with temperatures in the afternoons that reach, on average, to near 90 °F (32 °C). Overnight lows fall to near 68 °F (20 °C) ^[18] and there is usually an 8 °F (4 °C) difference in temperature between the mountains and Atlanta. While humidity in North Georgia, especially in the mountains, can be high it is not as high as it is in South Georgia. Summer thunderstorms add to the humidity in the area by providing 4.5 inches (110 mm) to 5.5 inches (140 mm) of rain during the summer months.

Although Georgia experiences many tropical cyclones,^[19] it only rarely experiences a direct hurricane strike due to its fairly small coastline. The last hurricane to directly affect the Georgia coastline was Hurricane David in 1979. The last major hurricane (Category 3 or higher) to hit the Georgia coast directly was in 1898. More common are hurricanes which strike the Florida Panhandle, weaken over land, and bring tropical storm or hurricane-force winds and heavy rain to the Georgia interior (especially the southwestern areas), as well as hurricanes that come close to the Georgia coastline, brushing the coast on their way up to hit the Carolinas.

Georgia is one of the leading states in incidents of tornadoes though they are rarely stronger than F1 .^[20] Southwestern and northern sections of the state have historically reported the largest amount of tornadoes.^[21] The areas closest to the Florida border report F0 and F1 tornadoes associated with summer afternoon thunderstorms. However, tornadoes of F3 intensity or greater within Georgia are uncommon, with three events reported on average each year.^[22]

Georgia's autumns are normally sunny and cool.^[23] September and October, the driest months of the year, qualify as "Indian Summer" weather with temperatures that are near 78 °F (26 °C) during the daytime. At night, the temperature drops to near 50 °F (10 °C). It is much cooler in November with an average high of 62 °F (17 °C) and low of 36 °F (2 °C). The first freeze of the year normally falls within November, except in the northern mountains, where it occurs in October.^[18]

• List of wettest known tropical cyclones in Georgia