Signal Mountain, TN climate
Signal Mountain has mild winters and warm summers, with plenty of rain. A typical July afternoon reaches 85°, a January night drops to 29°, and about 4 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Signal Mountain feels like
Winter
Spring
Summer
Fall
Signal Mountain weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 47° | 29° | 5.7" | 1.4" | 8 | 29° – 45° |
| February | 51° | 32° | 5.8" | 1.8" | 9 | 32° – 49° |
| March | 59° | 39° | 5.8" | 0.3" | 9 | 43° – 59° |
| April | 69° | 47° | 5.7" | 0 | 9 | 53° – 63° |
| May | 76° | 57° | 4.7" | 0 | 8 | 61° – 71° |
| June | 82° | 63° | 5.1" | 0 | 8 | 68° – 76° |
| July | 85° | 66° | 4.9" | 0 | 9 | 72° – 80° |
| August | 84° | 66° | 4.1" | 0 | 8 | 70° – 80° |
| September | 79° | 60° | 4.6" | 0 | 6 | 67° – 76° |
| October | 70° | 50° | 4.4" | 0 | 6 | 56° – 65° |
| November | 58° | 39° | 5.1" | 0 | 7 | 43° – 54° |
| December | 49° | 32° | 6.3" | 0.8" | 8 | 32° – 51° |
| Year | 67° | 48° | 62.4" | 4.3" | 95 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Signal Mountain
Signal Mountain gets 62 inches of rain and melted snow a year. December is the wettest month and August the driest. Rain or snow falls on about 95 days a year.
About 219 frost-free days a year
In half of years the last 32° night comes by March 31 and the first one by November 6. That leaves about 219 frost-free days for gardens, longer than 82% of U.S. towns.
Heating and cooling a home in Signal Mountain
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Signal Mountain, 77% of that work is heating and 23% is cooling.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Signal Mountain and its neighbors
Signal Mountain borders 3 towns with climate data. January nights across them vary by 2.7°. Fairmount has the coldest January nights (28°) and Chattanooga the hottest July afternoons (90°). Signal Mountain’s January low is 29° and its July high 85°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Signal Mountain compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Signal Mountain averaged 0.9° warmer than the 1900s. The biggest change is in December (+2.0°). The shift is smaller than in 75% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Signal Mountain’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 32° to 51°. July is the most reliable, staying within 8°.
Common questions about Signal Mountain’s climate
What is the coldest month in Signal Mountain?
January, with a typical high of 47° and a low of 29°.
What is the hottest month in Signal Mountain?
July, with a typical high of 85° and a low of 66°. About 7 days a year reach 90°.
How much snow does Signal Mountain get?
About 4 inches in a normal winter, most of it in February.
When is the first frost in Signal Mountain?
In half of years the first 32° night comes by November 6, and the last spring frost by March 31.
What is the rainiest month in Signal Mountain?
December, with 6.3 inches of rain and melted snow. The year totals 62 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Signal Mountain itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Soddy Daisy-mowbray Mtn, TN (11 mi, snow) and Lookout Mtn-point Park, TN (9 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.