Spencer, IA

Iowa · Records since 1895–2026

☁️ 81°F
Currently in Spencer
As of 1:30 PM CDT

Records for September 11

🔥 Record High

94°F

September 11, 2012

+16° from 78° normal

❄ Record Low

32°F

September 11, 1955

-20° from 52° normal
🌞 Normal high: 78°F 🌑 Normal low: 52°F 1991–2020 normals

All-Time Records — Spencer

🔥
113°F
Hottest Day Ever
Jul 17, 1936
❄
-38°F
Coldest Day Ever
Jan 12, 1912
🌧
5.50"
Wettest Day Ever
Sep 14, 2004
☃
14.0"
Most Snow in One Day
Mar 3, 1977

First & Last Dates — Spencer

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)
187 days
Longest growing season
1964
99 days
Shortest growing season
1896
145 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 94°F September 11, 2012
2 94°F September 11, 1931
3 94°F September 11, 1927
4 94°F September 11, 1895
5 93°F September 11, 1998
6 92°F September 11, 2005
7 92°F September 11, 1978
8 92°F September 11, 1948
9 90°F September 11, 1942
10 89°F September 11, 1990

Top 5 Record Lows — September 11

# Temp Date
🥶 32°F September 11, 1955
2 35°F September 11, 1959
3 35°F September 11, 1922
4 36°F September 11, 1896
5 37°F September 11, 2007
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 1895–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Spencer

threshold: 93°F (90th percentile of historical Jun–Aug highs)
4.3
Avg heat wave length
days (historical)
99°
Avg peak temp
during heat waves
6
Dangerous nights 2026
Overnights ≥ 70°F
0
Heat waves 2026
so far

Days ≥ 90°F Per Year

1895–2026
18
2026 so far
23
Avg/year 1970–2025
24
Avg/year (last 10 complete)
70
Most in a year (1936)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Spencer

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 4, 1936 – Jul 19, 1936 16 113°F (Jul 17) 106°F 70°F
2 Jul 12, 1932 – Jul 22, 1932 11 100°F (Jul 20) 96°F 69°F
3 Jul 31, 1930 – Aug 8, 1930 9 111°F (Aug 3) 99°F 69°F
4 Jul 4, 1930 – Jul 12, 1930 9 106°F (Jul 9) 101°F 69°F
5 Jul 25, 1987 – Aug 2, 1987 9 100°F (Jul 30) 97°F 70°F
6 Sep 5, 1931 – Sep 13, 1931 9 99°F (Sep 10) 96°F 69°F
7 Jul 28, 1955 – Aug 5, 1955 9 99°F (Jul 30) 96°F 71°F
8 Jul 21, 1936 – Jul 28, 1936 8 106°F (Jul 22) 99°F 67°F
9 Jul 18, 1940 – Jul 25, 1940 8 106°F (Jul 24) 102°F 72°F
10 Aug 13, 1972 – Aug 20, 1972 8 95°F (Aug 17) 94°F 69°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

39
2026 total
above-normal nights
39.4
Avg / summer
1970–2020
62
Most in a summer
1983

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 (1895–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1895, annual totals have trended +0.28" per decade, about +3.6" 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 Spencer is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

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

Precipitation, Year to Date

17.81"
2026 YTD
Normal: 20.89"
-3.08"
3.73"
September so far
September normal: 3.21"
+0.52"
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 · Spencer is 3.08" behind the normal pace

Period Review — Aug 11 – Sep 10, 2026

Any window, evaluated against every other year on record — 31 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
71.9°F
Average temperature
21st-warmest of 112
+3.1°
vs. average
Normal: 68.8°F (1991–2020)
5.72"
Precipitation
19th-wettest of 106
+2.73"
vs. average
Normal: 2.99" · 191% of normal

Average Temperature by Year — Aug 11 – Sep 10

1895–2026 · 2026 highlighted · trend -0.09° per decade (cooling since 1895)

Precipitation by Year — Aug 11 – Sep 10

1896–2026 · 2026 highlighted · trend -0.05" per decade (drier since 1896)

Warmest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 1936 77.0°F
2 1937 75.9°F
3 1947 75.5°F
4 1983 75.2°F
5 1922 75.0°F
6 1925 74.7°F
7 1978 73.9°F
8 1990 73.6°F
9 1913 73.5°F
10 1931 73.5°F

Coolest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 1946 63.1°F
2 1950 63.6°F
3 2008 64.6°F
4 1896 64.8°F
5 1967 64.9°F
6 1986 64.9°F
7 1962 65.0°F
8 1934 65.1°F
9 1987 65.2°F
10 1951 65.3°F

Wettest Aug 11 – Sep 10 on Record

# Year Total
1 1975 10.26"
2 1964 9.81"
3 1985 9.45"
4 1993 7.91"
5 2007 7.85"
6 1954 7.39"
7 1989 7.10"
8 1969 6.98"
9 1938 6.87"
10 1937 6.73"

Driest Aug 11 – Sep 10 on Record

# Year Total
1 1955 0.26"
2 1984 0.38"
3 1945 0.50"
4 1976 0.69"
5 1967 0.69"
6 1950 0.69"
7 2020 0.76"
8 2003 0.92"
9 2023 0.94"
10 2000 1.02"
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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