Sisseton, SD

South Dakota · Records since 1931–2026

☁️ 74°F
Currently in Sisseton
As of 1:30 PM CDT

Records for September 7

🔥 Record High

99°F

September 7, 1978

+22° from 77° normal

❄ Record Low

33°F

September 7, 2025

-18° from 51° normal
🌞 Normal high: 77°F 🌑 Normal low: 51°F 1991–2020 normals

All-Time Records — Sisseton

🔥
113°F
Hottest Day Ever
Jul 6, 1936
❄
-37°F
Coldest Day Ever
Jan 24, 1936
🌧
5.50"
Wettest Day Ever
May 27, 1954
☃
24.2"
Most Snow in One Day
Jan 4, 1997

Top 10 Record Highs — September 7

# Temp Date
🏆 99°F September 7, 1978
2 98°F September 7, 1933
3 97°F September 7, 2002
4 93°F September 7, 1976
5 93°F September 7, 1971
6 91°F September 7, 1980
7 91°F September 7, 1962
8 90°F September 7, 2013
9 89°F September 7, 2022
10 89°F September 7, 1970

Top 5 Record Lows — September 7

# Temp Date
🥶 33°F September 7, 2025
2 35°F September 7, 1956
3 37°F September 7, 1979
4 38°F September 7, 1986
5 39°F September 7, 2023
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 1931–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Sisseton

threshold: 92°F (90th percentile of historical Jun–Aug highs)
4.3
Avg heat wave length
days (historical)
99°
Avg peak temp
during heat waves
3
Dangerous nights 2026
Overnights ≥ 70°F
1
Heat waves 2026
so far

2026 Daily High Temperature vs Normal

Year to date
Above normal Below normal

139 of 249 days with data were above the 1991–2020 normal high for their date.

Days ≥ 90°F Per Year

1932–2026
18
2026 so far
19
Avg/year 1970–2025
16
Avg/year (last 10 complete)
65
Most in a year (1934)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Sisseton

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 4, 1936 – Jul 19, 1936 16 113°F (Jul 6) 103°F 69°F
2 Aug 17, 1976 – Aug 27, 1976 11 105°F (Aug 18) 100°F 68°F
3 Jul 20, 1941 – Jul 28, 1941 9 104°F (Jul 24) 98°F 73°F
4 May 26, 1934 – Jun 2, 1934 8 113°F (May 30) 103°F 63°F
5 Jul 17, 1934 – Jul 24, 1934 8 112°F (Jul 22) 102°F 70°F
6 Jul 14, 1932 – Jul 21, 1932 8 106°F (Jul 19) 99°F 68°F
7 Jul 17, 1940 – Jul 24, 1940 8 105°F (Jul 24) 100°F 69°F
8 Jul 26, 1988 – Aug 2, 1988 8 102°F (Jul 27) 98°F 69°F
9 Jun 3, 2021 – Jun 10, 2021 8 101°F (Jun 5) 97°F 67°F
10 Jul 16, 1974 – Jul 23, 1974 8 98°F (Jul 17) 96°F 66°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

52
2026 total
above-normal nights
44.0
Avg / summer
1970–2020
67
Most in a summer
2022

Above-Normal Summer Nights Per Year

Average June–August Low by Decade

Overnight lows · complete decades only

Precipitation

Actual vs. 1991–2020 full-month and full-season normals

15.52"
2026 YTD
Normal: 17.34"
-1.82"
0.01"
September so far
September normal: 2.45"
-2.44"
3
2026 heavy rain days
Days with ≥ 1.0"

2026 Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Sisseton is 1.82" behind the normal pace

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1931–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1931, annual totals have trended +0.40" per decade, about +3.7" across the record.

Heavy Rain Days Per Year (≥ 1.0")

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

Month in Review — August 2026

68.7°F

Average temperature · August 2026

175th-warmest month on record

65th-warmest August of 94 on record

-0.1° vs. 68.8° average (1991–2020)
80.6°F
Warmest month ever
July 1936
77.1°F
Warmest August ever
1983
94°F
Hottest of 2026
May 25

Average August Temperature by Year

1932–2026 · 2026 highlighted · trend -0.29° per decade (cooling since 1932)

Precipitation — August 2026

Month total against the 1991–2020 average and every other August on record

0.23"
Total precipitation
August 2026
-2.18"
vs. average
Normal: 2.41" · 10% of normal
3rd-driest
August rank
of 93 on record
7.98"
Wettest August ever
2021 · driest 0.13" (2003)

August Precipitation by Year

1931–2026 · 2026 highlighted · trend +0.05" per decade (wetter since 1931)

Wettest Augusts on Record

# Year Total
1 2021 7.98"
2 1964 6.91"
3 1941 6.49"
4 2023 6.45"
5 1966 6.36"
6 1989 6.03"
7 1957 5.40"
8 2017 5.30"
9 1980 5.25"
10 1983 5.06"

Driest Augusts on Record

# Year Total
1 2003 0.13"
2 1969 0.14"
3 2026 0.23"
4 1946 0.32"
5 1970 0.40"
6 1996 0.60"
7 1962 0.62"
8 1938 0.63"
9 2004 0.67"
10 1933 0.77"

Warmest Augusts on Record

# Year Avg Temp
1 1983 77.1°F
2 1969 76.0°F
3 1976 75.9°F
4 1947 75.8°F
5 1973 75.3°F
6 1959 74.9°F
7 1949 74.7°F
8 1937 74.7°F
9 1961 74.6°F
10 1955 74.4°F

Warmest Months on Record (Any Month)

# Month Avg Temp
1 July 1936 80.6°F
2 July 1983 77.5°F
3 July 1974 77.5°F
4 July 1975 77.4°F
5 August 1983 77.1°F
6 July 1988 76.8°F
7 July 1966 76.7°F
8 July 1934 76.3°F
9 July 1976 76.2°F
10 August 1969 76.0°F

Nearby Stations — August 2026

How the same month ranked at the closest reporting stations

Station Avg Temp August Rank
Sisseton, SD 68.7°F 65th of 94
Aberdeen, SD 69.9°F 72nd of 132
Fargo, ND 71.0°F 29th of 146
Huron, SD 72.4°F 53rd of 146
Saint Cloud, MN 69.7°F 39th of 130
About this data. Monthly averages are the mean of daily average temperatures, computed from NOAA Threadex records via RCC ACIS. Months missing more than three days of observations are excluded from the rankings, so the in-progress month never appears. Rankings cover 1,093 complete months on record. Precipitation totals sum the daily reports for the month, with trace amounts counted as zero. A month missing any day of precipitation data is left out entirely (an unreported day is unreported rain), so the precipitation ranking covers 93 complete Augusts. Normals are the 1991–2020 mean for the same calendar month. Trend lines are a least-squares fit across every year shown.

Fall in Review — Fall 2026

September 1 – November 30, 2026

Fall 2026 is still under way. Season totals and rankings appear once November closes; the markers below update as they happen.

Summer to Winter — 2026

Each turning point of the season against its 1991–2020 normal date, with the earliest and latest on record

Marker 2026 Normal vs. normal Earliest Latest Drift
Last 90°F day
The final day of summer heat
 Sep 3
so far
 Aug 31 May 30, 2014 Oct 15, 1958 -1.4 d/decade
Last 80°F day
The last genuinely warm afternoon
 Sep 6
so far
 Oct 5 Aug 31, 1986 Oct 31, 1933 -0.7 d/decade
First high below 50°F
The first afternoon that stays cold
 not yet Oct 9 Sep 14, 1986 Nov 11, 1963 +0.2 d/decade
First 32°F freeze
Growing season over
 not yet Sep 29 Sep 9, 2020 Oct 29, 1963 +0.4 d/decade
First 28°F hard freeze
Cold enough to end tender growth
 not yet Oct 9 Sep 11, 1964 Oct 29, 1975 +0.1 d/decade
First 20°F night
Winter cold arriving
 not yet Oct 30 Oct 2, 1974 Nov 27, 1944 +0.4 d/decade
First measurable snow
0.1" or more in a day
 not yet Nov 9 Sep 26, 1942 Dec 22, 2006 -0.9 d/decade

Drift is a least-squares fit across every year on record. Positive means the marker has been arriving later.

First Freeze by Year

The first 32°F night of each autumn since 1932 · trending +0.4 days later per decade

147
Normal length
1991–2020 average
172
Longest on record
2024
112
Shortest on record
1935

Growing Season Length by Year

Days between the last spring freeze and the first fall freeze · trending +1.5 days longer per decade

Fall Average Temperature by Year

1932–2025 · 2026 highlighted

Fall Precipitation by Year

1933–2025 · 2026 highlighted · trend +0.33" per decade (wetter since 1933)

About this data. Fall is meteorological autumn, September 1 through November 30, the window NOAA uses for seasonal statistics. Seasonal temperature is the day-weighted mean of the three monthly means; precipitation is their sum, and a season missing any of the three months is left out of the rankings. Freeze, heat and snow markers come from daily NOAA Threadex observations via RCC ACIS: freezes and snow are the first occurrence on or after July 1, and the last 90°F and 80°F days are the final ones anywhere in the calendar year. Growing season counts the freeze-free days between the last spring 32°F and the first fall 32°F.
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