Sioux Falls, SD

South Dakota · Records since 1893–2026

⛅ 84°F
Currently in Sioux Falls
As of 1:30 PM CDT

Records for September 11

🔥 Record High

96°F

September 11, 2012

+18° from 78° normal

❄ Record Low

28°F

September 11, 1894

-26° from 54° normal
🌞 Normal high: 78°F 🌑 Normal low: 54°F 1991–2020 normals

All-Time Records — Sioux Falls

🔥
110°F
Hottest Day Ever
Jun 21, 1988
❄
-42°F
Coldest Day Ever
Feb 9, 1899
🌧
5.44"
Wettest Day Ever
Aug 7, 2022
☃
18.1"
Most Snow in One Day
Mar 10, 1956

First & Last Dates — Sioux Falls

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)
196 days
Longest growing season
1938
101 days
Shortest growing season
1897
150 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 96°F September 11, 2012
2 96°F September 11, 1895
3 95°F September 11, 1908
4 93°F September 11, 1990
5 93°F September 11, 1905
6 91°F September 11, 1978
7 91°F September 11, 1963
8 91°F September 11, 1931
9 90°F September 11, 1998
10 90°F September 11, 1948

Top 5 Record Lows — September 11

# Temp Date
🥶 28°F September 11, 1894
2 33°F September 11, 1898
3 34°F September 11, 1955
4 36°F September 11, 1940
5 36°F September 11, 1896
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 1893–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Sioux Falls

threshold: 93°F (90th percentile of historical Jun–Aug highs)
4.4
Avg heat wave length
days (historical)
100°
Avg peak temp
during heat waves
17
Dangerous nights 2026
Overnights ≥ 70°F
1
Heat waves 2026
so far

Days ≥ 90°F Per Year

1893–2026
27
2026 so far
23
Avg/year 1970–2025
23
Avg/year (last 10 complete)
66
Most in a year (1894)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Sioux Falls

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 2, 1936 – Jul 19, 1936 18 110°F (Jul 17) 102°F 73°F
2 Jun 17, 1910 – Jul 2, 1910 16 98°F (Jun 20) 95°F 66°F
3 Jul 13, 2012 – Jul 25, 2012 13 102°F (Jul 24) 98°F 72°F
4 Jul 17, 1940 – Jul 25, 1940 9 105°F (Jul 18) 100°F 71°F
5 Jul 28, 1955 – Aug 5, 1955 9 101°F (Jul 30) 98°F 73°F
6 Jul 16, 1974 – Jul 24, 1974 9 101°F (Jul 17) 98°F 70°F
7 Jul 25, 1987 – Aug 2, 1987 9 101°F (Jul 30) 97°F 72°F
8 Jul 26, 1988 – Aug 2, 1988 8 107°F (Jul 31) 98°F 69°F
9 Jun 28, 1966 – Jul 5, 1966 8 101°F (Jul 4) 96°F 70°F
10 Aug 13, 1972 – Aug 20, 1972 8 98°F (Aug 17) 96°F 72°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

55
2026 total
above-normal nights
38.4
Avg / summer
1970–2020
66
Most in a summer
1936

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 (1893–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1893, annual totals have trended +0.09" per decade, about +1.2" 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 Sioux Falls is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

152 of 253 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

13.98"
2026 YTD
Normal: 21.63"
-7.65"
0.87"
September so far
September normal: 2.73"
-1.86"
4
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Sioux Falls is 7.65" behind the normal pace

Period Review — Jun 1 – Aug 31, 2026

Any window, evaluated against every other year on record — 92 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
73.6°F
Average temperature
19th-warmest of 133
+2.4°
vs. average
Normal: 71.1°F (1991–2020)
5.65"
Precipitation
9th-driest of 133
-5.16"
vs. average
Normal: 10.81" · 52% of normal

Average Temperature by Year — Jun 1 – Aug 31

1893–2026 · 2026 highlighted · trend +0.12° per decade (warming since 1893)

Precipitation by Year — Jun 1 – Aug 31

1893–2026 · 2026 highlighted · trend -0.04" per decade (drier since 1893)

Warmest Jun 1 – Aug 31 on Record

# Year Avg Temp
1 1936 77.9°F
2 1988 76.2°F
3 2020 75.5°F
4 2012 75.3°F
5 2021 75.1°F
6 2023 74.9°F
7 1938 74.6°F
8 1955 74.6°F
9 1976 74.5°F
10 1937 74.4°F

Coolest Jun 1 – Aug 31 on Record

# Year Avg Temp
1 1915 63.8°F
2 1992 66.2°F
3 2004 66.9°F
4 1903 67.2°F
5 1950 67.3°F
6 1985 67.4°F
7 1951 67.5°F
8 2009 67.5°F
9 1945 67.6°F
10 1902 67.7°F

Wettest Jun 1 – Aug 31 on Record

# Year Total
1 2010 22.64"
2 2014 19.45"
3 2018 17.56"
4 1993 17.39"
5 1909 17.18"
6 1944 16.76"
7 1992 16.14"
8 1900 15.82"
9 1934 15.66"
10 2015 15.05"

Driest Jun 1 – Aug 31 on Record

# Year Total
1 2012 2.73"
2 1894 3.55"
3 1976 3.86"
4 1996 3.91"
5 1927 4.82"
6 1893 4.90"
7 1988 5.42"
8 1958 5.61"
9 2026 5.65"
10 1917 5.68"
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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