Record envelope, standing records and threshold days for Knoxville Exp STN (USC00404946), Tennessee, United States, with 60 years of record.
Key Facts for Knoxville Exp STN
Knoxville Exp STN (USC00404946) is a weather station in Tennessee, United States at 35.90 latitude and -83.96 longitude, 253 m (830 ft) above sea level.
The station reports from 1966 to 2025, 60 years of record.
1,464 records set at Knoxville Exp STN still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Knoxville Exp STN set a daily record high minimum temperature of 23.9 C (75.0 F) on 20 July 2025.
About the Station
Location: Tennessee, United States, 35.90 latitude, -83.96 longitude.
Elevation: 253 m (830 ft).
Period of record: 1966 to 2025, 60 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
6 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Knoxville Exp STN. The lines show the 2026 daily maximum and minimum. 6 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Knoxville Exp STN, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
25.6 C (78.1 F)
-28.9 C (-20.0 F)
12.2 C (54.0 F)
-14.4 C (6.1 F)
Feb
27.8 C (82.0 F)
-24.4 C (-11.9 F)
23.3 C (73.9 F)
-9.4 C (15.1 F)
Mar
30.0 C (86.0 F)
-16.7 C (1.9 F)
26.1 C (79.0 F)
-6.1 C (21.0 F)
Apr
32.2 C (90.0 F)
-6.1 C (21.0 F)
30.0 C (86.0 F)
-1.1 C (30.0 F)
May
33.9 C (93.0 F)
-1.1 C (30.0 F)
30.0 C (86.0 F)
7.8 C (46.0 F)
Jun
38.3 C (100.9 F)
5.6 C (42.1 F)
36.1 C (97.0 F)
12.8 C (55.0 F)
Jul
40.6 C (105.1 F)
8.9 C (48.0 F)
35.0 C (95.0 F)
18.3 C (64.9 F)
Aug
38.9 C (102.0 F)
8.9 C (48.0 F)
31.7 C (89.1 F)
15.0 C (59.0 F)
Sep
36.1 C (97.0 F)
2.8 C (37.0 F)
n/a
n/a
Oct
35.0 C (95.0 F)
-5.0 C (23.0 F)
29.4 C (84.9 F)
1.1 C (34.0 F)
Nov
28.9 C (84.0 F)
-9.4 C (15.1 F)
n/a
n/a
Dec
25.6 C (78.1 F)
-20.6 C (-5.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Knoxville Exp STN still stand. 2018 holds the most, with 58.
Standing records at Knoxville Exp STN by the year they were set
Year set
Standing records
1966
9
1967
10
1968
16
1969
11
1970
1
1971
9
1972
16
1973
4
1974
28
1975
11
1976
15
1979
9
1980
2
1981
6
1982
38
1983
41
1984
38
1985
31
1986
38
1987
6
1988
50
1989
46
1990
21
1991
39
1992
29
1993
30
1994
17
1995
33
1996
41
1997
31
1998
24
1999
36
2000
25
2001
28
2002
46
2003
16
2004
28
2005
17
2006
19
2007
36
2008
18
2009
15
2010
40
2011
24
2012
32
2013
24
2014
30
2015
41
2016
46
2017
42
2018
58
2019
31
2020
20
2021
10
2022
29
2023
23
2024
23
2025
7
All-Time Record Progression
5 new records
5 all-time records were set at Knoxville Exp STN between 24 May 2000 and 16 January 2024. Each dot is a new record.
When Knoxville Exp STN set new all-time records
Date
Kind
Detail
2000-05-24
Record daily precipitation
Record daily precipitation 125.0 mm (4.9 in)
2006-09-24
Record daily precipitation
Record daily precipitation 130.8 mm (5.1 in)
2012-09-18
Record daily precipitation
Record daily precipitation 169.2 mm (6.7 in)
2024-01-16
Record daily snowfall
Record daily snowfall 28.7 cm (11.3 in)
2024-01-16
Record snow depth
Record snow depth 27.9 cm (11.0 in)
Wettest Day of Each Month
Sep: 169.2 mm (6.7 in)
The wettest day on record for each calendar month at Knoxville Exp STN. The most was 169.2 mm (6.7 in) on 18 September 2012.
Record daily precipitation for each month at Knoxville Exp STN
Month
Record daily precipitation (mm)
Date
Jan
77.5 mm (3.1 in)
7 January 2009
Feb
149.1 mm (5.9 in)
24 February 2019
Mar
101.1 mm (4.0 in)
16 March 1973
Apr
97.5 mm (3.8 in)
28 April 2011
May
125.0 mm (4.9 in)
24 May 2000
Jun
82.8 mm (3.3 in)
4 June 2024
Jul
112.5 mm (4.4 in)
23 July 2019
Aug
78.7 mm (3.1 in)
18 August 2021
Sep
169.2 mm (6.7 in)
18 September 2012
Oct
67.6 mm (2.7 in)
8 October 2021
Nov
84.3 mm (3.3 in)
28 November 1973
Dec
118.4 mm (4.7 in)
1 December 2016
Period of Record Coverage
1966 to 2025
Complete yearUnder 90 percent of days
58 years of record at Knoxville Exp STN, 1966 to 2025. 20 years have data for under 90 percent of days and are left out of rankings: 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 33 complete years at Knoxville Exp STN, 1983 to 2024. Blue stripes are years cooler than the station's own mean of 14.6 C (58.3 F); red stripes are warmer. The coolest year was 1996, at 13.4 C (56.2 F), and the warmest was 2016, at 16.0 C (60.7 F). The strongest colour marks a difference of 1.4 C (2.5 F).
Annual mean temperature at Knoxville Exp STN as warming stripes, 1983 to 2024
Year
Annual mean temperature
Difference from the station mean
1983
13.8 C
-0.83 C
1986
14.8 C
+0.18 C
1990
15.0 C
+0.31 C
1991
14.9 C
+0.24 C
1992
13.7 C
-0.97 C
1993
13.9 C
-0.79 C
1994
13.9 C
-0.75 C
1995
13.9 C
-0.76 C
1996
13.4 C
-1.22 C
1997
13.9 C
-0.76 C
1998
14.6 C
-0.07 C
1999
14.2 C
-0.43 C
2000
14.4 C
-0.25 C
2001
14.7 C
+0.02 C
2002
15.1 C
+0.48 C
2003
14.4 C
-0.22 C
2005
13.8 C
-0.83 C
2008
14.3 C
-0.31 C
2009
14.3 C
-0.30 C
2010
14.4 C
-0.23 C
2012
15.8 C
+1.12 C
2013
14.1 C
-0.54 C
2014
13.9 C
-0.75 C
2015
15.2 C
+0.56 C
2016
16.0 C
+1.33 C
2017
15.8 C
+1.17 C
2018
15.3 C
+0.67 C
2019
15.5 C
+0.82 C
2020
14.9 C
+0.21 C
2021
15.3 C
+0.65 C
2022
15.1 C
+0.46 C
2023
15.9 C
+1.24 C
2024
15.1 C
+0.45 C
The annual mean temperature here has risen by 0.4 C (0.2 to 0.5) per decade over 1983 to 2024. In Fahrenheit: 0.7 F (0.3 to 1.0) per decade. The slope is a straight line fitted to 33 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Knoxville Exp STN
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.4 C (0.2 to 0.5) per decade
0.7 F (0.3 to 1.0) per decade
1983 to 2024
33
Rise
Mean daily maximum
0.3 C (0.1 to 0.6) per decade
0.6 F (0.2 to 1.0) per decade
1983 to 2024
33
Rise
Mean daily minimum
0.4 C (0.2 to 0.6) per decade
0.7 F (0.4 to 1.0) per decade
1983 to 2024
33
Rise
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1966 to 2025
Yearly extremes at Knoxville Exp STN: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
40.6 C (105.1 F)
2012
35.0 C (95.0 F)
58
Coldest night (TNn)
-28.9 C (-20.0 F)
1985
-13.9 C (7.0 F)
58
Wettest day (Rx1day)
169.2 mm (6.7 in)
2012
68.6 mm (2.7 in)
60
Wettest five days (Rx5day)
224.0 mm (8.8 in)
2019
122.5 mm (4.8 in)
60
Longest dry spell (CDD)
40 days
2016
17 days
60
Hottest day (TXx)
The hottest day of the year at Knoxville Exp STN, 1966 to 2025. The record is 40.6 C (105.1 F) in 2012, marked on the chart; the median year is 35.0 C (95.0 F).
Hottest day (TXx) at Knoxville Exp STN by year
Year
Hottest day (TXx)
1966
31.7 C (89.1 F)
1967
26.7 C (80.1 F)
1968
37.8 C (100.0 F)
1969
32.8 C (91.0 F)
1970
31.1 C (88.0 F)
1971
22.2 C (72.0 F)
1972
34.4 C (93.9 F)
1973
35.0 C (95.0 F)
1974
33.9 C (93.0 F)
1975
29.4 C (84.9 F)
1976
32.2 C (90.0 F)
1977
n/a
1978
n/a
1979
33.9 C (93.0 F)
1980
31.7 C (89.1 F)
1981
35.0 C (95.0 F)
1982
34.4 C (93.9 F)
1983
38.9 C (102.0 F)
1984
33.9 C (93.0 F)
1985
35.6 C (96.1 F)
1986
36.7 C (98.1 F)
1987
31.7 C (89.1 F)
1988
37.8 C (100.0 F)
1989
32.8 C (91.0 F)
1990
36.1 C (97.0 F)
1991
35.6 C (96.1 F)
1992
33.3 C (91.9 F)
1993
36.7 C (98.1 F)
1994
32.2 C (90.0 F)
1995
36.7 C (98.1 F)
1996
34.4 C (93.9 F)
1997
35.0 C (95.0 F)
1998
35.0 C (95.0 F)
1999
36.1 C (97.0 F)
2000
35.0 C (95.0 F)
2001
33.9 C (93.0 F)
2002
36.7 C (98.1 F)
2003
33.3 C (91.9 F)
2004
32.2 C (90.0 F)
2005
35.0 C (95.0 F)
2006
36.1 C (97.0 F)
2007
38.9 C (102.0 F)
2008
33.9 C (93.0 F)
2009
33.9 C (93.0 F)
2010
37.2 C (99.0 F)
2011
36.1 C (97.0 F)
2012
40.6 C (105.1 F)
2013
33.3 C (91.9 F)
2014
33.3 C (91.9 F)
2015
34.4 C (93.9 F)
2016
36.7 C (98.1 F)
2017
35.6 C (96.1 F)
2018
35.6 C (96.1 F)
2019
35.0 C (95.0 F)
2020
35.0 C (95.0 F)
2021
36.7 C (98.1 F)
2022
36.1 C (97.0 F)
2023
36.1 C (97.0 F)
2024
36.7 C (98.1 F)
2025
36.1 C (97.0 F)
Coldest night (TNn)
The coldest night of the year at Knoxville Exp STN, 1966 to 2025. The record is -28.9 C (-20.0 F) in 1985, marked on the chart; the median year is -13.9 C (7.0 F).
Coldest night (TNn) at Knoxville Exp STN by year
Year
Coldest night (TNn)
1966
-5.6 C (21.9 F)
1967
-7.8 C (18.0 F)
1968
-7.8 C (18.0 F)
1969
-9.4 C (15.1 F)
1970
-3.3 C (26.1 F)
1971
-17.2 C (1.0 F)
1972
-17.8 C (0.0 F)
1973
6.1 C (43.0 F)
1974
-6.1 C (21.0 F)
1975
-10.0 C (14.0 F)
1976
-5.0 C (23.0 F)
1977
n/a
1978
n/a
1979
-16.7 C (1.9 F)
1980
-1.1 C (30.0 F)
1981
-15.0 C (5.0 F)
1982
-22.2 C (-8.0 F)
1983
-20.6 C (-5.1 F)
1984
-15.6 C (3.9 F)
1985
-28.9 C (-20.0 F)
1986
-17.8 C (0.0 F)
1987
-13.9 C (7.0 F)
1988
-14.4 C (6.1 F)
1989
-18.3 C (-0.9 F)
1990
-10.0 C (14.0 F)
1991
-14.4 C (6.1 F)
1992
-12.8 C (9.0 F)
1993
-16.7 C (1.9 F)
1994
-21.7 C (-7.1 F)
1995
-14.4 C (6.1 F)
1996
-24.4 C (-11.9 F)
1997
-13.3 C (8.1 F)
1998
-12.2 C (10.0 F)
1999
-12.8 C (9.0 F)
2000
-11.7 C (10.9 F)
2001
-13.3 C (8.1 F)
2002
-11.1 C (12.0 F)
2003
-15.6 C (3.9 F)
2004
-14.4 C (6.1 F)
2005
-15.6 C (3.9 F)
2006
-11.1 C (12.0 F)
2007
-11.7 C (10.9 F)
2008
-12.2 C (10.0 F)
2009
-13.9 C (7.0 F)
2010
-13.9 C (7.0 F)
2011
-11.7 C (10.9 F)
2012
-9.4 C (15.1 F)
2013
-8.3 C (17.1 F)
2014
-21.1 C (-6.0 F)
2015
-18.3 C (-0.9 F)
2016
-13.9 C (7.0 F)
2017
-16.1 C (3.0 F)
2018
-14.4 C (6.1 F)
2019
-11.7 C (10.9 F)
2020
-12.2 C (10.0 F)
2021
-6.7 C (19.9 F)
2022
-17.8 C (0.0 F)
2023
-6.7 C (19.9 F)
2024
-20.0 C (-4.0 F)
2025
-14.4 C (6.1 F)
Wettest day (Rx1day)
The wettest day of the year at Knoxville Exp STN, 1966 to 2025. The record is 169.2 mm (6.7 in) in 2012, marked on the chart; the median year is 68.6 mm (2.7 in).
Wettest day (Rx1day) at Knoxville Exp STN by year
Year
Wettest day (Rx1day)
1966
70.9 mm (2.8 in)
1967
84.8 mm (3.3 in)
1968
45.0 mm (1.8 in)
1969
91.4 mm (3.6 in)
1970
48.5 mm (1.9 in)
1971
37.1 mm (1.5 in)
1972
77.5 mm (3.1 in)
1973
101.1 mm (4.0 in)
1974
82.3 mm (3.2 in)
1975
63.5 mm (2.5 in)
1976
50.8 mm (2.0 in)
1977
61.0 mm (2.4 in)
1978
71.1 mm (2.8 in)
1979
61.7 mm (2.4 in)
1980
80.3 mm (3.2 in)
1981
56.1 mm (2.2 in)
1982
78.7 mm (3.1 in)
1983
63.8 mm (2.5 in)
1984
96.5 mm (3.8 in)
1985
46.5 mm (1.8 in)
1986
39.1 mm (1.5 in)
1987
74.4 mm (2.9 in)
1988
63.0 mm (2.5 in)
1989
58.9 mm (2.3 in)
1990
84.8 mm (3.3 in)
1991
78.0 mm (3.1 in)
1992
47.2 mm (1.9 in)
1993
78.0 mm (3.1 in)
1994
88.4 mm (3.5 in)
1995
40.4 mm (1.6 in)
1996
56.4 mm (2.2 in)
1997
68.6 mm (2.7 in)
1998
81.3 mm (3.2 in)
1999
63.5 mm (2.5 in)
2000
125.0 mm (4.9 in)
2001
64.0 mm (2.5 in)
2002
63.5 mm (2.5 in)
2003
68.6 mm (2.7 in)
2004
52.6 mm (2.1 in)
2005
61.2 mm (2.4 in)
2006
130.8 mm (5.1 in)
2007
42.2 mm (1.7 in)
2008
49.5 mm (1.9 in)
2009
77.5 mm (3.1 in)
2010
62.5 mm (2.5 in)
2011
114.0 mm (4.5 in)
2012
169.2 mm (6.7 in)
2013
73.9 mm (2.9 in)
2014
61.5 mm (2.4 in)
2015
59.2 mm (2.3 in)
2016
118.4 mm (4.7 in)
2017
79.0 mm (3.1 in)
2018
67.8 mm (2.7 in)
2019
149.1 mm (5.9 in)
2020
96.5 mm (3.8 in)
2021
78.7 mm (3.1 in)
2022
50.5 mm (2.0 in)
2023
75.9 mm (3.0 in)
2024
82.8 mm (3.3 in)
2025
42.2 mm (1.7 in)
Wettest five days (Rx5day)
The wettest five days of the year at Knoxville Exp STN, 1966 to 2025. The record is 224.0 mm (8.8 in) in 2019, marked on the chart; the median year is 122.5 mm (4.8 in).
Wettest five days (Rx5day) at Knoxville Exp STN by year
Year
Wettest five days (Rx5day)
1966
95.2 mm (3.7 in)
1967
103.1 mm (4.1 in)
1968
74.2 mm (2.9 in)
1969
164.9 mm (6.5 in)
1970
159.6 mm (6.3 in)
1971
79.8 mm (3.1 in)
1972
142.5 mm (5.6 in)
1973
166.4 mm (6.6 in)
1974
95.8 mm (3.8 in)
1975
128.0 mm (5.0 in)
1976
74.9 mm (2.9 in)
1977
153.9 mm (6.1 in)
1978
88.9 mm (3.5 in)
1979
87.3 mm (3.4 in)
1980
126.6 mm (5.0 in)
1981
113.8 mm (4.5 in)
1982
147.0 mm (5.8 in)
1983
107.5 mm (4.2 in)
1984
162.8 mm (6.4 in)
1985
73.2 mm (2.9 in)
1986
90.8 mm (3.6 in)
1987
100.3 mm (3.9 in)
1988
76.1 mm (3.0 in)
1989
101.6 mm (4.0 in)
1990
143.7 mm (5.7 in)
1991
183.6 mm (7.2 in)
1992
90.4 mm (3.6 in)
1993
108.8 mm (4.3 in)
1994
178.6 mm (7.0 in)
1995
71.4 mm (2.8 in)
1996
83.4 mm (3.3 in)
1997
95.1 mm (3.7 in)
1998
156.0 mm (6.1 in)
1999
122.3 mm (4.8 in)
2000
156.0 mm (6.1 in)
2001
123.1 mm (4.8 in)
2002
139.2 mm (5.5 in)
2003
122.7 mm (4.8 in)
2004
130.0 mm (5.1 in)
2005
82.0 mm (3.2 in)
2006
139.4 mm (5.5 in)
2007
67.9 mm (2.7 in)
2008
120.6 mm (4.7 in)
2009
117.1 mm (4.6 in)
2010
108.2 mm (4.3 in)
2011
170.7 mm (6.7 in)
2012
172.8 mm (6.8 in)
2013
208.3 mm (8.2 in)
2014
89.2 mm (3.5 in)
2015
136.6 mm (5.4 in)
2016
151.4 mm (6.0 in)
2017
100.9 mm (4.0 in)
2018
163.9 mm (6.5 in)
2019
224.0 mm (8.8 in)
2020
160.7 mm (6.3 in)
2021
144.5 mm (5.7 in)
2022
146.8 mm (5.8 in)
2023
118.4 mm (4.7 in)
2024
167.2 mm (6.6 in)
2025
83.8 mm (3.3 in)
Longest dry spell (CDD)
The longest dry spell of the year at Knoxville Exp STN, 1966 to 2025. The record is 40 days in 2016, marked on the chart; the median year is 17 days.
Longest dry spell (CDD) at Knoxville Exp STN by year
Year
Longest dry spell (CDD)
1966
20 days
1967
17 days
1968
25 days
1969
12 days
1970
17 days
1971
15 days
1972
22 days
1973
10 days
1974
19 days
1975
18 days
1976
14 days
1977
19 days
1978
15 days
1979
11 days
1980
24 days
1981
15 days
1982
12 days
1983
16 days
1984
25 days
1985
23 days
1986
19 days
1987
11 days
1988
17 days
1989
14 days
1990
13 days
1991
16 days
1992
20 days
1993
17 days
1994
11 days
1995
14 days
1996
14 days
1997
16 days
1998
34 days
1999
27 days
2000
31 days
2001
25 days
2002
17 days
2003
11 days
2004
12 days
2005
16 days
2006
11 days
2007
13 days
2008
18 days
2009
11 days
2010
16 days
2011
14 days
2012
14 days
2013
9 days
2014
13 days
2015
21 days
2016
40 days
2017
24 days
2018
21 days
2019
27 days
2020
29 days
2021
16 days
2022
29 days
2023
23 days
2024
29 days
2025
16 days
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
33 years with a frost
Across 33 years with a frost, the median last spring frost at Knoxville Exp STN falls on 9 April and the median first autumn frost on 28 October, which leaves a median of 199 days between them.
Fitted over all years, the growing season changes by +1.6 days per decade at this station.
Frost dates and growing season at Knoxville Exp STN
Measure
Median, all years
Earliest period
Recent period (1991 to 2024)
Recent against earliest
Fitted trend
Last spring frost
9 April
n/a
9 April
n/a
-0.7 days per decade
First autumn frost
28 October
n/a
28 October
n/a
+0.8 days per decade
Growing days
199 days
n/a
199 days
n/a
+1.6 days per decade
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
55 years, 1966 to 2024
A day with at least 67.7 mm (2.7 in) of rain is expected about once in 2 years. A day with at least 169.1 mm (6.7 in) of rain is expected about once in 100 years.
Rainfall return levels at Knoxville Exp STN: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
67.7 mm (2.7 in)
5 years
90.3 mm (3.6 in)
10 years
106.9 mm (4.2 in)
25 years
130.0 mm (5.1 in)
50 years
148.9 mm (5.9 in)
100 years
169.1 mm (6.7 in)
Longer than the 55 years of record
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 55 years of values from 1966 to 2024.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 169.2 mm (6.7 in) in 2012; 149.1 mm (5.9 in) in 2019; 130.8 mm (5.1 in) in 2006.
Download the Data
Data for Knoxville Exp STN standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Knoxville Exp STN threshold days by year: CSV or JSON. Field meanings are on the data page.
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-15 (15 October 2026). Records are computed by this site and are not official.