Rapid City Downtown, SD

South Dakota · Records since 1888–2026

⛅ 91°F Feels like 87°
Currently in Rapid City Downtown
As of 12:45 PM MDT

Records for September 7

🔥 Record High

102°F

September 7, 1908

+24° from 78° normal

❄ Record Low

31°F

September 7, 2020

-23° from 54° normal
🌞 Normal high: 78°F 🌑 Normal low: 54°F 1991–2020 normals

All-Time Records — Rapid City Downtown

🔥
110°F
Hottest Day Ever
Jul 25, 2026
❄
-34°F
Coldest Day Ever
Feb 11, 1899
🌧
5.57"
Wettest Day Ever
May 27, 1926
☃
20.0"
Most Snow in One Day
Apr 18, 1970

Top 10 Record Highs — September 7

# Temp Date
🏆 102°F September 7, 1908
2 101°F September 7, 1931
3 98°F September 7, 1897
4 96°F September 7, 2022
5 95°F September 7, 1963
6 95°F September 7, 1952
7 95°F September 7, 1947
8 95°F September 7, 1893
9 94°F September 7, 2013
10 94°F September 7, 2002

Top 5 Record Lows — September 7

# Temp Date
🥶 31°F September 7, 2020
2 34°F September 7, 1929
3 35°F September 7, 1890
4 38°F September 7, 1898
5 38°F September 7, 1895
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 1888–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Rapid City Downtown

threshold: 94°F (90th percentile of historical Jun–Aug highs)
3.8
Avg heat wave length
days (historical)
101°
Avg peak temp
during heat waves
13
Dangerous nights 2026
Overnights ≥ 70°F
3
Heat waves 2026
so far

2026 Daily High Temperature vs Normal

Year to date
Above normal Below normal

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

Days ≥ 90°F Per Year

1888–2026
47
2026 so far
25
Avg/year 1970–2025
29
Avg/year (last 10 complete)
55
Most in a year (1936)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Rapid City Downtown

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 2, 1936 – Jul 11, 1936 10 106°F (Jul 5) 102°F 71°F
2 Jul 21, 1931 – Jul 27, 1931 7 105°F (Jul 25) 100°F 70°F
3 Jul 10, 2026 – Jul 16, 2026 7 105°F (Jul 12) 101°F 68°F
4 Jul 18, 2012 – Jul 24, 2012 7 103°F (Jul 19) 98°F 68°F
5 Sep 4, 1931 – Sep 10, 1931 7 101°F (Sep 7) 98°F 64°F
6 Jul 24, 2026 – Jul 29, 2026 6 110°F (Jul 25) 102°F 70°F
7 Jul 8, 1954 – Jul 13, 1954 6 107°F (Jul 9) 101°F 70°F
8 Jul 21, 1936 – Jul 26, 1936 6 106°F (Jul 23) 99°F 68°F
9 Jul 17, 1934 – Jul 22, 1934 6 104°F (Jul 18) 100°F 70°F
10 Jul 14, 1936 – Jul 19, 1936 6 104°F (Jul 19) 100°F 70°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

59
2026 total
above-normal nights
44.7
Avg / summer
1970–2020
63
Most in a summer
1936

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

11.16"
2026 YTD
Normal: 16.55"
-5.39"
0.02"
September so far
September normal: 1.40"
-1.38"
2
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 · Rapid City Downtown is 5.39" behind the normal pace

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1888–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1888, annual totals have trended +0.18" per decade, about +2.5" 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

74.7°F

Average temperature · August 2026

42nd-warmest month on record

13th-warmest August of 115 on record

+3.0° vs. 71.8° average (1991–2020)
82.4°F
Warmest month ever
July 1936
77.3°F
Warmest August ever
1961
11
Days ≥ 90°F
in August
110°F
Hottest of 2026
Jul 25

Longest 90°F Streak in August

3 consecutive days with highs of at least 90°F (Aug 27–29, 2026, peaking at 93°F)

Ties the longest August streak since 2025 (1 year). The August record is 10 days, set in 1936.

Average August Temperature by Year

1888–2026 · 2026 highlighted · trend +0.24° per decade (warming since 1888)

Precipitation — August 2026

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

4.16"
Total precipitation
August 2026
+1.94"
vs. average
Normal: 2.22" · 187% of normal
7th-wettest
August rank
of 114 on record
5.67"
Wettest August ever
1906 · driest 0.09" (1944)

August Precipitation by Year

1888–2026 · 2026 highlighted · trend +0.05" per decade (wetter since 1888)

Wettest Augusts on Record

# Year Total
1 1906 5.67"
2 1888 4.76"
3 2014 4.75"
4 2007 4.65"
5 1951 4.23"
6 1945 4.19"
7 2026 4.16"
8 1997 3.94"
9 2019 3.81"
10 1932 3.78"

Driest Augusts on Record

# Year Total
1 1944 0.09"
2 1889 0.11"
3 1896 0.13"
4 1935 0.19"
5 1969 0.31"
6 1919 0.35"
7 1894 0.35"
8 1943 0.36"
9 2012 0.38"
10 1928 0.42"

Warmest Augusts on Record

# Year Avg Temp
1 1961 77.3°F
2 1937 76.7°F
3 2022 76.4°F
4 1955 76.2°F
5 2003 76.0°F
6 1959 75.7°F
7 1969 75.7°F
8 1947 75.5°F
9 1970 75.4°F
10 1936 75.0°F

Warmest Months on Record (Any Month)

# Month Avg Temp
1 July 1936 82.4°F
2 July 2026 80.7°F
3 July 2012 79.2°F
4 July 2017 78.4°F
5 July 2006 78.3°F
6 July 2007 78.1°F
7 July 1954 77.9°F
8 July 1966 77.8°F
9 July 2021 77.5°F
10 July 2003 77.5°F

Nearby Stations — August 2026

How the same month ranked at the closest reporting stations

Station Avg Temp August Rank
Rapid City Downtown, SD 74.7°F 13th of 115
Rapid City, SD 73.1°F 26th of 85
Scottsbluff, NE 74.9°F 15th of 130
Valentine, NE 73.2°F 53rd of 138
Mobridge, SD 71.6°F 63rd of 107
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 1,376 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 114 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 6
so far
 Sep 15 Aug 20, 1946 Oct 9, 2003 +0.5 d/decade
Last 80°F day
The last genuinely warm afternoon
 Sep 6
so far
 Oct 9 Sep 15, 1959 Nov 8, 1999
First high below 50°F
The first afternoon that stays cold
 not yet Sep 27 Sep 6, 1929 Nov 13, 1964
First 32°F freeze
Growing season over
 not yet Oct 8 Sep 7, 2020 Oct 31, 2024 +0.9 d/decade
First 28°F hard freeze
Cold enough to end tender growth
 not yet Oct 19 Sep 14, 1904 Nov 5, 2024 +0.8 d/decade
First 20°F night
Winter cold arriving
 not yet Nov 3 Sep 24, 1926 Dec 9, 1962 +0.4 d/decade
First measurable snow
0.1" or more in a day
 not yet Oct 21 Sep 7, 2020 Dec 7, 1963

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 1888 · trending +0.9 days later per decade

154
Normal length
1991–2020 average
196
Longest on record
1940
111
Shortest on record
1949

Growing Season Length by Year

Days between the last spring freeze and the first fall freeze · trending +1.3 days longer per decade

Fall Average Temperature by Year

1888–2025 · 2026 highlighted · trend +0.18° per decade (warming since 1888)

Fall Precipitation by Year

1888–2025 · 2026 highlighted · trend +0.07" per decade (wetter since 1888)

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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