Knoxville Experiment Station, Tennessee climate: Climate normals at a NOAA weather station
Knoxville Experiment Station's normal year runs from 26°F January nights to 88°F July afternoons, with 55.8 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 14.4°C, January lows of −3°C, July highs of 31°C, 1,417 mm of precipitation a year.
- NOAA stationKnoxville Experiment Station
- Station IDUSC00404946
- Location35.90°N 83.96°W
- Elevation830 ft (253 m)
On October 23, the normal high in Knoxville Experiment Station is 70°F and the normal low 42°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Knoxville Experiment Station.
- Jan 48° 26°
- Feb 53° 29°
- Mar 61° 36°
- Apr 71° 44°
- May 79° 54°
- Jun 86° 62°
- Jul 88° 66°
- Aug 88° 65°
- Sep 83° 59°
- Oct 72° 46°
- Nov 61° 35°
- Dec 51° 30°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Knoxville Experiment Station each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 26°F. The most precipitation falls in December (5.91 in), the least in October (3.05 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 48°F | 26°F | 37.1°F | 5.23 | 12 | <1 | 22 | 10 h |
| February | 53°F | 29°F | 40.9°F | 5.12 | 11 | <1 | 18 | 10 h 50 min |
| March | 61°F | 36°F | 48.5°F | 5.28 | 13 | <1 | 11 | 11 h 50 min |
| April | 71°F | 44°F | 57.3°F | 5.25 | 11 | <1 | 3 | 13 h |
| May | 79°F | 54°F | 66.1°F | 4.53 | 12 | 1 | <1 | 14 h |
| June | 86°F | 62°F | 73.7°F | 3.96 | 11 | 7 | <1 | 14 h 30 min |
| July | 88°F | 66°F | 77.2°F | 5.82 | 12 | 12 | <1 | 14 h 20 min |
| August | 88°F | 65°F | 76.4°F | 3.42 | 10 | 11 | <1 | 13 h 30 min |
| September | 83°F | 59°F | 70.8°F | 4.13 | 9 | 5 | <1 | 12 h 30 min |
| October | 72°F | 46°F | 59.0°F | 3.05 | 8 | <1 | 2 | 11 h 20 min |
| November | 61°F | 35°F | 47.6°F | 4.10 | 9 | <1 | 13 | 10 h 20 min |
| December | 51°F | 30°F | 40.4°F | 5.91 | 12 | <1 | 19 | 9 h 40 min |
| Year (annual) | 70°F | 46°F | 57.9°F | 55.80 | 128 | 36 | 87 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 9°C | −3°C | 2.8°C | 133 mm |
| February | 11°C | −1°C | 4.9°C | 130 mm |
| March | 16°C | 2°C | 9.2°C | 134 mm |
| April | 22°C | 7°C | 14.1°C | 133 mm |
| May | 26°C | 12°C | 18.9°C | 115 mm |
| June | 30°C | 17°C | 23.2°C | 101 mm |
| July | 31°C | 19°C | 25.1°C | 148 mm |
| August | 31°C | 18°C | 24.7°C | 87 mm |
| September | 28°C | 15°C | 21.6°C | 105 mm |
| October | 22°C | 8°C | 15.0°C | 77 mm |
| November | 16°C | 2°C | 8.7°C | 104 mm |
| December | 11°C | −1°C | 4.7°C | 150 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Knoxville (6 miles away), gets 5 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00404946; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Knoxville Experiment Station?
Normal highs sit between 65°F and 85°F in April, May, September and October. Of those, October has the fewest days with rain (8).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00404946.
When is the last frost at Knoxville Experiment Station?
In Knoxville Experiment Station, the last spring frost (32°F) comes after April 11 in half of years and after April 29 in one year in ten; the first autumn frost comes before October 28 in half of years and before October 13 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 111 year in 10 after April 29; 9 in 10 after March 26
- First autumn frost, half of years before
- October 281 year in 10 before October 13; 9 in 10 before November 9
NOAA puts the median frost-free season at 198 days, and the season without a hard freeze (28°F) at 221 days.
A hard freeze (28°F) comes after March 31 in half of springs and before November 6 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Knoxville Experiment Station in zone 7b in ZIP code 37919, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 7b: the coldest night of a typical year reaches 6°F (28 complete years).
Frost dates for every NOAA station in Tennessee · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00404946; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Knoxville Experiment Station?
In a normal year in Knoxville Experiment Station, 36 days a year reach 90°F, 87 nights fall to 32°F or colder and 128 days bring measurable precipitation.
- Days at 90°F or more
- 36a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 87a normal year
- Days that stay below freezing
- 5high of 32°F or less
- Days with 0.01 inch of precipitation
- 128a normal year
The highest temperature in this station's record (since 1966) is 105°F, on July 1, 2012; the lowest is −20°F, on January 21, 1985.
The wettest calendar year on that record is 2018, with 72.95 in; the snowiest season is 1969–70, with 12.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00404946; records: ACIS (NOAA Regional Climate Centers), station USC00404946. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Knoxville Experiment Station?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds at Knoxville Experiment Station, 4.3 kWh per square metre a day. August is the sunniest month (77%) and February the cloudiest (65%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 2.5 |
| February | 65% | 3.0 |
| March | 69% | 4.1 |
| April | 73% | 5.3 |
| May | 74% | 5.8 |
| June | 76% | 6.1 |
| July | 75% | 5.8 |
| August | 77% | 5.4 |
| September | 76% | 4.7 |
| October | 76% | 3.8 |
| November | 76% | 2.9 |
| December | 68% | 2.2 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Knoxville Experiment Station record?
A normal year at Knoxville Experiment Station brings 3,911 heating degree days, 27% fewer than the median U.S. place (5,373), and 1,364 cooling degree days, 50% more than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,278 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 863 | 0 |
| February | 675 | 0 |
| March | 513 | 2 |
| April | 252 | 21 |
| May | 74 | 110 |
| June | 5 | 268 |
| July | 0 | 380 |
| August | 1 | 352 |
| September | 23 | 196 |
| October | 219 | 34 |
| November | 522 | 2 |
| December | 763 | 0 |
| Year (annual) | 3,911 | 1,364 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00404946. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Knoxville Experiment Station been warmer than normal?
2024 averaged 59.2°F, 1.3°F above the 1991-2020 normal of 57.9°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 59.5°F | +1.6°F | 55.29 |
| 2022 | 59.2°F | +1.3°F | 60.82 |
| 2023 | 60.6°F | +2.7°F | 55.42 |
| 2024 | 59.2°F | +1.3°F | 55.35 |
Source: observed years: ACIS, station USC00404946. A year counts only with all twelve months complete.
How does Knoxville Experiment Station's climate compare?
Knoxville Experiment Station is warmer than 40 of the 116 places with their own NOAA record in Tennessee, and wetter than 54. Across the 7,247 U.S. stations with normals, its annual mean of 57.9°F is warmer than 69%.
In the Köppen classification computed from these normals, Knoxville Experiment Station is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Knoxville Experiment Station share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Powell, TN13,544 people · 10 mi NW
- John Sevier, TN987 people · 12 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Knoxville Experiment Station's climate
What is the coldest month at Knoxville Experiment Station?
January, with a normal high of 48°F and a normal low of 26°F. The warmest is July (88°F by day, 66°F at night).
Does it snow at Knoxville Experiment Station?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Knoxville (6 miles away), records 5 inches of snow in a normal year.
What is the rainiest month at Knoxville Experiment Station?
December, with 5.91 in of precipitation in a normal year; the driest is October with 3.05 in.
What plant hardiness zone is Knoxville Experiment Station in?
The USDA's 2023 map puts Knoxville Experiment Station in zone 7b in ZIP code 37919, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 6°F (28 years, 1991-2020): zone 7b.
How late can frost come at Knoxville Experiment Station?
In half of years the last 32°F night comes after April 11; in one year in ten it comes after April 29. Waiting until April 29 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Tennessee climateThe statewide normals and every place in the state
- Knoxville, TN6 miles from this station, 59.6°F a year
- Oak Ridge Atdd, TN18 miles from this station, 58.6°F a year
- Oak Ridge, TN18 miles from this station, 59.8°F a year
- Lenoir City, TN19 miles from this station, 59.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made