The Look Rock webcam on the western edge of the park captured a photo of a lightning strike during a spring storm. Severe storms, including tornados, occur in the park, especially during spring and summer.
Common wildflowers in the Smokies: trillium, fringed phacelia, and phlox.
Thom McManus
Spring
March through May brings unpredictable weather. Changes occur rapidly—sunny skies can yield to snow flurries in a few hours.
Snow can fall at any time during March, particularly in the higher elevations. Temperatures in the lower elevations have a mean high of 61ºF. Low temperatures, which are often below freezing, have a mean of 42ºF.
By mid-April, the weather is usually milder with daytime temperatures in the 70s and occasionally the 80s. Below freezing temperatures at night are uncommon in the lower elevations but still occur higher up.
April averages over 4 inches (10.2 centimeters) of rain, usually in the form of afternoon showers.
May is warmer, with daytime highs in the 70s and 80s and lows in the 40s and 50s. May rainfall averages about 4.5 inches (11.4 centimeters).
Andrews Bald, reached via the Forney Ridge Trail, boasts sweeping views.
Andrea Walton
Summer
June through August means heat, haze, and humidity. Afternoon showers and thunderstorms are common.
Temperatures increase through the period with July and August afternoon highs in the 90s in the lower elevations. Evening lows are usually comfortable with readings in the 60s and 70s. In the higher elevations, the weather is much more pleasant.
On Mount Le Conte (6,593 feet/2,010 meters high), temperatures above 80 degrees Fahrenheit are extremely rare.
Mt. Sterling as seen from Mt. Cammerer in fall.
Bob Carr
Autumn
September through mid-November welcomes cooler weather that signals the onset of the fall color season. Warm days alternate with cool nights.
Daytime highs are usually in the 70s and 80s during September, falling to the 50s and 60s in early November.
The first frosts often occur in late September. By November, the lows are usually near freezing. This is the driest period of the year with only occasional rain showers. In the higher elevations, snow is a possibility by November.
A view along the Little River Trail in winter.
Bob Carr
Winter
Mid-November through February is generally moderate, but weather extremes do occur, especially with an increase in elevation. It is not unusual to have warm temperatures in the low elevations and snow in the higher areas.
About half the days in the winter have high temperatures of 50 degrees or more. Highs occasionally even reach the 70s.
Most nights have lows at or below freezing, but lows of -20°F are possible at high elevations. In the low elevations, snows of 1" or more occur 1-5 times a year. Snow falls more frequently in the higher mountains and up to two feet can fall during a storm.
One is most likely to find snow in the mountains in January and February.
Average Monthly Temperatures & Precipitation
The following tables give monthly averages for weather in the park. Temperatures are in degrees Fahrenheit. Precipitation and snow are listed in inches. T = trace.
For Gatlinburg, TN (low elevation)
Month
High
Low
Monthly Precipitation
Monthly Snowfall
Days of Precipitation
Jan
51
28
4.8"
2.3"
9
Feb
54
29
4.8"
2.9"
9
March
61
34
5.3"
T
8
April
71
42
4.5"
0
8
May
79
50
4.5"
0
9
June
86
58
5.2"
0
9
July
88
59
5.7"
0
10
Aug
87
60
5.3"
0
10
Sept
83
55
3.0"
0
5
Oct
73
43
3.1"
T
6
Nov
61
33
3.4"
0.7"
7
Dec
52
28
4.5"
1.0"
8
For Kuwohi (formerly Clingmans Dome) (high elevation)
Month
High
Low
Monthly Precipitation
Monthly Snowfall
Days of Precipitation
Jan
35
19
7.0"
18"
12
Feb
35
18
8.2"
20"
12
March
39
24
8.2"
26"
12
April
49
34
6.5"
5"
10
May
57
43
6.0"
T
10
June
63
49
6.9"
0
11
July
65
53
8.3"
0
13
Aug
64
52
6.8"
0
12
Sept
60
47
5.1"
T
8
Oct
53
38
5.4"
2"
8
Nov
42
28
6.4"
5"
9
Dec
37
21
7.3"
8"
10
Drought
Keetch and Byram (1968) designed a drought index specifically for fire potential assessment. It is a number representing the net effect of evapotranspiration and precipitation in producing cumulative moisture deficiency in deep duff and upper soil layers. It is a continuous index, relating to the flammability of organic material in the ground.
The KBDI attempts to measure the amount of precipitation necessary to return the soil to full field capacity. It is a closed system ranging from 0 to 800 units and represents a moisture regime from 0 to 8 inches of water through the soil layer. At 8 inches of water, the KBDI assumes saturation. Zero is the point of no moisture deficiency and 800 is the maximum drought that is possible. At any point along the scale, the index number indicates the amount of net rainfall that is required to reduce the index to zero, or saturation.
The inputs for KBDI are weather station latitude, mean annual precipitation, maximum dry bulb temperature, and the last 24 hours of rainfall. Reduction in drought occurs only when rainfall exceeds 0.20 inch (called net rainfall). The computational steps involve reducing the drought index by the net rain amount and increasing the drought index by a drought factor.
KBDI = 0 - 200: Soil moisture and large class fuel moistures are high and do not contribute much to fire intensity. Typical of spring dormant season following winter precipitation.
KBDI = 200 - 400: Typical of late spring, early growing season. Lower litter and duff layers are drying and beginning to contribute to fire intensity.
KBDI = 400 - 600: Typical of late summer, early fall. Lower litter and duff layers actively contribute to fire intensity and will burn actively.
KBDI = 600 - 800: Often associated with more severe drought with increased wildfire occurrence. Intense, deep burning fires with significant downwind spotting can be expected. Live fuels can also be expected to burn actively at these levels.
