Knoxville, TN

Tennessee · Records since 1871–2026

🌙 62°F
Currently in Knoxville
As of 10:15 PM EDT

Records for September 26

🔥 Record High

89°F

September 26, 2019

+10° from 79° normal

❄ Record Low

41°F

September 26, 2001

-17° from 58° normal
🌞 Normal high: 79°F 🌑 Normal low: 58°F 1991–2020 normals

All-Time Records — Knoxville

🔥
105°F
Hottest Day Ever
Jul 1, 2012
❄
-24°F
Coldest Day Ever
Jan 21, 1985
🌧
6.14"
Wettest Day Ever
Jul 16, 1917
☃
17.5"
Most Snow in One Day
Feb 13, 1960

First & Last Dates — Knoxville

How early and how late each seasonal turning point has ever arrived, across the full period of record

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Range ever recorded Normal date (1991–2020)
262 days
Longest growing season
1978
175 days
Shortest growing season
1988
214 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 26

# Temp Date
🏆 89°F September 26, 2019
2 89°F September 26, 1986
3 89°F September 26, 1958
4 89°F September 26, 1933
5 89°F September 26, 1895
6 88°F September 26, 2017
7 88°F September 26, 2016
8 88°F September 26, 2007
9 88°F September 26, 1998
10 88°F September 26, 1923

Top 5 Record Lows — September 26

# Temp Date
🥶 41°F September 26, 2001
2 42°F September 26, 1928
3 44°F September 26, 1943
4 44°F September 26, 1879
5 45°F September 26, 1899
About this data — Records are sourced from the NOAA Threadex dataset via RCC ACIS, a quality-controlled record for long-term climate stations. Threadex adjusts for station relocations and observation-time changes, making records comparable across all years since 1871–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Knoxville

threshold: 93°F (90th percentile of historical Jun–Aug highs)
4.9
Avg heat wave length
days (historical)
97°
Avg peak temp
during heat waves
68
Dangerous nights 2026
Overnights ≥ 70°F
3
Heat waves 2026
so far

Days ≥ 90°F Per Year

1871–2026
57
2026 so far
34
Avg/year 1970–2025
43
Avg/year (last 10 complete)
78
Most in a year (1936)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Knoxville

# Dates Days Peak Avg High Avg Overnight Low
🏆 Aug 7, 2007 – Aug 29, 2007 23 102°F (Aug 23) 96°F 72°F
2 Jul 16, 1986 – Jul 30, 1986 15 98°F (Jul 19) 96°F 71°F
3 Jul 11, 1951 – Jul 24, 1951 14 98°F (Jul 22) 95°F 70°F
4 Jul 18, 1952 – Jul 30, 1952 13 103°F (Jul 27) 98°F 72°F
5 Jul 2, 1993 – Jul 14, 1993 13 100°F (Jul 8) 96°F 71°F
6 Jul 18, 1993 – Jul 29, 1993 12 100°F (Jul 28) 97°F 72°F
7 Jun 28, 2012 – Jul 8, 2012 11 105°F (Jun 30) 99°F 70°F
8 Jun 19, 1931 – Jun 29, 1931 11 101°F (Jun 27) 97°F 72°F
9 Jul 11, 1980 – Jul 21, 1980 11 101°F (Jul 17) 96°F 74°F
10 Jul 26, 2011 – Aug 5, 2011 11 99°F (Aug 3) 96°F 72°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

Nights where the overnight low exceeded the 1991–2020 normal low

69
2026 total
above-normal nights
46.3
Avg / summer
1970–2020
76
Most in a summer
2016

Above-Normal Summer Nights Per Year

Average June–August Low by Decade

Overnight lows · complete decades only

Precipitation

Annual totals and trend across the full period of record · see this year's standing →

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1871–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1871, annual totals have trended +0.10" per decade, about +1.6" across the record.

Heavy Rain Days Per Year (≥ 1.0")

Compare year-to-year changes in days with heavy rainfall (≥ 1.0")

This Year — 2026

How Knoxville is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

178 of 267 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

34.48"
2026 YTD
Normal: 39.29"
-4.81"
1.99"
September so far
September normal: 3.49"
-1.50"
13
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Knoxville is 4.81" behind the normal pace

Period Review — Sep 1 – Sep 25, 2026

Any window, evaluated against every other year on record — 25 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
80.4°F
Average temperature
2nd-warmest of 156
+7.5°
vs. average
Normal: 72.9°F (1991–2020)

Average Temperature by Year — Sep 1 – Sep 25

1871–2026 · 2026 highlighted · trend +0.11° per decade (warming since 1871)

Precipitation by Year — Sep 1 – Sep 25

1871–2025 · 2026 highlighted · trend +0.03" per decade (wetter since 1871)

Warmest Sep 1 – Sep 25 on Record

# Year Avg Temp
1 1925 80.8°F
2 2026 80.4°F
3 1931 79.8°F
4 1921 78.8°F
5 2016 78.2°F
6 1926 78.1°F
7 2019 78.0°F
8 2018 77.6°F
9 1970 77.4°F
10 1911 77.1°F

Coolest Sep 1 – Sep 25 on Record

# Year Avg Temp
1 1918 65.7°F
2 1924 67.2°F
3 1967 67.6°F
4 1902 67.8°F
5 1976 67.9°F
6 1928 68.2°F
7 1875 68.3°F
8 1901 68.3°F
9 1984 68.4°F
10 1966 68.6°F
About this data. Pick any start and end date and this becomes the same kind of review as the Month and Fall tabs, just for exactly the window you asked for — the generalized version of the same engine, evaluated across every year on record. Average temperature is the mean of each day's (high + low) / 2; precipitation is the sum of daily totals. A year missing more than about a fifth of the window's days is excluded from the temperature ranking; any missing day excludes a year from the precipitation ranking, since an unreported day is unreported rain. Ranges that cross from December into January aren't supported yet. Normals are the 1991–2020 mean for the same window.
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