Sioux City, IA

Iowa · Records since 1889–2026

☁️ 84°F
Currently in Sioux City
As of 1:30 PM CDT

Records for September 11

🔥 Record High

98°F

September 11, 2012

+20° from 78° normal

❄ Record Low

35°F

September 11, 1894

-18° from 53° normal
🌞 Normal high: 78°F 🌑 Normal low: 53°F 1991–2020 normals

All-Time Records — Sioux City

🔥
111°F
Hottest Day Ever
Jul 11, 1939
❄
-35°F
Coldest Day Ever
Jan 12, 1912
🌧
5.50"
Wettest Day Ever
Jul 17, 1972
☃
20.0"
Most Snow in One Day
Apr 10, 1913

First & Last Dates — Sioux City

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)
213 days
Longest growing season
1905
123 days
Shortest growing season
1997
156 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 98°F September 11, 2012
2 96°F September 11, 1939
3 96°F September 11, 1895
4 94°F September 11, 2005
5 94°F September 11, 1948
6 93°F September 11, 1931
7 92°F September 11, 1998
8 92°F September 11, 1990
9 92°F September 11, 1978
10 92°F September 11, 1927

Top 5 Record Lows — September 11

# Temp Date
🥶 35°F September 11, 1894
2 36°F September 11, 1955
3 36°F September 11, 1940
4 38°F September 11, 1896
5 40°F September 11, 2022
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 1889–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Sioux City

threshold: 94°F (90th percentile of historical Jun–Aug highs)
4.4
Avg heat wave length
days (historical)
100°
Avg peak temp
during heat waves
18
Dangerous nights 2026
Overnights ≥ 70°F
1
Heat waves 2026
so far

Days ≥ 90°F Per Year

1889–2026
34
2026 so far
28
Avg/year 1970–2025
30
Avg/year (last 10 complete)
73
Most in a year (1936)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Sioux City

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 9, 1901 – Jul 27, 1901 19 106°F (Jul 21) 100°F 73°F
2 Jul 3, 1936 – Jul 19, 1936 17 111°F (Jul 4) 104°F 78°F
3 Jul 25, 1955 – Aug 5, 1955 12 107°F (Jul 31) 100°F 74°F
4 Aug 8, 1936 – Aug 18, 1936 11 105°F (Aug 15) 99°F 74°F
5 Jul 16, 1934 – Jul 25, 1934 10 107°F (Jul 20) 102°F 76°F
6 Jul 17, 1974 – Jul 26, 1974 10 103°F (Jul 18) 99°F 72°F
7 Jun 25, 1990 – Jul 3, 1990 9 104°F (Jul 3) 96°F 72°F
8 Jul 2, 1937 – Jul 10, 1937 9 103°F (Jul 7) 97°F 72°F
9 Jul 21, 1936 – Jul 28, 1936 8 108°F (Jul 25) 101°F 74°F
10 Jul 17, 1940 – Jul 24, 1940 8 107°F (Jul 24) 100°F 73°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
48.1
Avg / summer
1970–2020
72
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 (1889–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1889, annual totals have trended +0.35" per decade, about +4.7" 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 City is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

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

Precipitation, Year to Date

17.91"
2026 YTD
Normal: 22.99"
-5.08"
0.96"
September so far
September normal: 2.84"
-1.88"
5
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 City is 5.08" behind the normal pace

Period Review — Sep 3 – Sep 10, 2026

Any window, evaluated against every other year on record — 8 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
75.8°F
Average temperature
14th-warmest of 138
+8.2°
vs. average
Normal: 67.6°F (1991–2020)
0.54"
Precipitation
57th-wettest of 138
-0.38"
vs. average
Normal: 0.92" · 59% of normal

Average Temperature by Year — Sep 3 – Sep 10

1889–2026 · 2026 highlighted

Precipitation by Year — Sep 3 – Sep 10

1889–2026 · 2026 highlighted

Warmest Sep 3 – Sep 10 on Record

# Year Avg Temp
1 1931 82.9°F
2 1933 80.6°F
3 1913 80.4°F
4 1947 79.8°F
5 2005 79.1°F
6 1897 79.1°F
7 1938 78.3°F
8 1925 77.8°F
9 1990 77.7°F
10 1978 76.9°F

Coolest Sep 3 – Sep 10 on Record

# Year Avg Temp
1 2008 57.1°F
2 1929 57.9°F
3 1962 58.2°F
4 1918 59.4°F
5 2025 59.4°F
6 1993 60.8°F
7 1898 61.0°F
8 1896 61.3°F
9 1905 61.3°F
10 1934 61.5°F

Wettest Sep 3 – Sep 10 on Record

# Year Total
1 1949 5.53"
2 1914 5.05"
3 1938 4.83"
4 2003 4.39"
5 1989 4.33"
6 2009 3.07"
7 1977 2.90"
8 2018 2.75"
9 1926 2.71"
10 1916 2.66"

Driest Sep 3 – Sep 10 on Record

# Year Total
1 2024 0.00"
2 2021 0.00"
3 1998 0.00"
4 1990 0.00"
5 1988 0.00"
6 1978 0.00"
7 1959 0.00"
8 1955 0.00"
9 1952 0.00"
10 1950 0.00"
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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