Rapid City, SD

South Dakota · Records since 1942–2026

☁️ 89°F Feels like 85°
Currently in Rapid City
As of 12:15 PM MDT

Records for September 7

🔥 Record High

99°F

September 7, 1983

+19° from 80° normal

❄ Record Low

32°F

September 7, 2020

-18° from 50° normal
🌞 Normal high: 80°F 🌑 Normal low: 50°F 1991–2020 normals

All-Time Records — Rapid City

🔥
112°F
Hottest Day Ever
Jul 25, 2026
❄
-31°F
Coldest Day Ever
Feb 2, 1996
🌧
3.78"
Wettest Day Ever
Jun 15, 1963
☃
20.0"
Most Snow in One Day
Apr 9, 2013

Top 10 Record Highs — September 7

# Temp Date
🏆 99°F September 7, 1983
2 99°F September 7, 1978
3 98°F September 7, 2002
4 98°F September 7, 1947
5 97°F September 7, 2013
6 97°F September 7, 1952
7 96°F September 7, 1991
8 96°F September 7, 1963
9 94°F September 7, 2022
10 93°F September 7, 1994

Top 5 Record Lows — September 7

# Temp Date
🥶 32°F September 7, 2020
2 34°F September 7, 1986
3 38°F September 7, 2010
4 39°F September 7, 2000
5 39°F September 7, 1992
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 1942–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Rapid City

threshold: 96°F (90th percentile of historical Jun–Aug highs)
3.7
Avg heat wave length
days (historical)
103°
Avg peak temp
during heat waves
7
Dangerous nights 2026
Overnights ≥ 70°F
2
Heat waves 2026
so far

2026 Daily High Temperature vs Normal

Year to date
Above normal Below normal

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

Days ≥ 90°F Per Year

1942–2026
52
2026 so far
32
Avg/year 1970–2025
35
Avg/year (last 10 complete)
59
Most in a year (1988)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Rapid City

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 25, 1987 – Aug 2, 1987 9 105°F (Jul 25) 102°F 68°F
2 Jul 18, 2012 – Jul 24, 2012 7 107°F (Jul 19) 100°F 65°F
3 Jul 10, 2026 – Jul 16, 2026 7 105°F (Jul 12) 101°F 66°F
4 Jul 26, 1988 – Aug 1, 1988 7 104°F (Jul 30) 101°F 64°F
5 Aug 2, 2001 – Aug 8, 2001 7 104°F (Aug 7) 100°F 66°F
6 Aug 22, 1991 – Aug 28, 1991 7 103°F (Aug 25) 100°F 63°F
7 Jul 24, 2026 – Jul 29, 2026 6 112°F (Jul 25) 103°F 66°F
8 Jul 8, 1954 – Jul 13, 1954 6 109°F (Jul 12) 102°F 68°F
9 Jul 18, 1964 – Jul 23, 1964 6 104°F (Jul 21) 100°F 66°F
10 Jul 29, 1955 – Aug 3, 1955 6 102°F (Aug 1) 99°F 68°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
44.8
Avg / summer
1970–2020
74
Most in a summer
2007

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

9.75"
2026 YTD
Normal: 14.23"
-4.48"
0.13"
September so far
September normal: 1.22"
-1.09"
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 · Rapid City is 4.48" behind the normal pace

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1942–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1942, annual totals have trended +0.19" per decade, about +1.6" 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

73.1°F

Average temperature · August 2026

63rd-warmest month on record

26th-warmest August of 85 on record

+1.9° vs. 71.2° average (1991–2020)
79.7°F
Warmest month ever
July 2007
78.0°F
Warmest August ever
1983
16
Days ≥ 90°F
in August
112°F
Hottest of 2026
Jul 25

Longest 90°F Streak in August

4 consecutive days with highs of at least 90°F (Aug 8–11, 2026, peaking at 97°F)

The longest August streak since 2025 (1 year). The August record is 15 days, set in 2003.

Average August Temperature by Year

1942–2026 · 2026 highlighted

Precipitation — August 2026

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

2.17"
Total precipitation
August 2026
+0.58"
vs. average
Normal: 1.59" · 136% of normal
23rd-wettest
August rank
of 85 on record
4.83"
Wettest August ever
1982 · driest 0.10" (1943)

August Precipitation by Year

1942–2026 · 2026 highlighted · trend +0.06" per decade (wetter since 1942)

Wettest Augusts on Record

# Year Total
1 1982 4.83"
2 1945 4.40"
3 2014 4.02"
4 1997 3.93"
5 2015 3.41"
6 1966 3.24"
7 1956 3.15"
8 1948 3.06"
9 2025 2.96"
10 1951 2.92"

Driest Augusts on Record

# Year Total
1 1943 0.10"
2 1942 0.24"
3 1958 0.26"
4 1969 0.31"
5 1959 0.36"
6 1961 0.43"
7 1944 0.45"
8 1995 0.46"
9 1947 0.46"
10 2003 0.47"

Warmest Augusts on Record

# Year Avg Temp
1 1983 78.0°F
2 1961 77.2°F
3 1955 76.2°F
4 2003 75.9°F
5 1959 75.7°F
6 1947 75.3°F
7 1984 74.8°F
8 1958 74.7°F
9 2000 74.4°F
10 2001 74.4°F

Warmest Months on Record (Any Month)

# Month Avg Temp
1 July 2007 79.7°F
2 July 2006 79.3°F
3 July 2026 79.3°F
4 July 2012 78.4°F
5 July 2002 78.3°F
6 August 1983 78.0°F
7 July 1954 77.7°F
8 July 1974 77.3°F
9 August 1961 77.2°F
10 July 2017 77.1°F

Nearby Stations — August 2026

How the same month ranked at the closest reporting stations

Station Avg Temp August Rank
Rapid City, SD 73.1°F 26th of 85
Rapid City Downtown, SD 74.7°F 13th of 115
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 1,009 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 85 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 22 Aug 20, 1946 Oct 16, 1991 +0.6 d/decade
Last 80°F day
The last genuinely warm afternoon
 Sep 6
so far
 Oct 15 Aug 31, 1986 Nov 8, 1999 +0.4 d/decade
First high below 50°F
The first afternoon that stays cold
 not yet Oct 1 Sep 9, 1962 Nov 5, 1968 +0.7 d/decade
First 32°F freeze
Growing season over
 not yet Sep 27 Sep 7, 2020 Oct 27, 1963
First 28°F hard freeze
Cold enough to end tender growth
 not yet Oct 9 Sep 10, 1962 Nov 3, 1998 -0.1 d/decade
First 20°F night
Winter cold arriving
 not yet Oct 25 Sep 22, 1995 Nov 20, 1949 -0.5 d/decade
First measurable snow
0.1" or more in a day
 not yet Oct 27 Aug 9, 1950 Dec 5, 2017 +1.1 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 1942

135
Normal length
1991–2020 average
186
Longest on record
1977
110
Shortest on record
1949

Growing Season Length by Year

Days between the last spring freeze and the first fall freeze · trending -0.4 days shorter per decade

Fall Average Temperature by Year

1942–2025 · 2026 highlighted

Fall Precipitation by Year

1942–2025 · 2026 highlighted · trend +0.06" per decade (wetter since 1942)

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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