Rapid City Downtown, SD

South Dakota · Records since 1888–2026

🌙 64°F
Currently in Rapid City Downtown
As of 8:15 PM MDT

Records for September 26

🔥 Record High

96°F

September 26, 2024

+27° from 69° normal

❄ Record Low

19°F

September 26, 1934

-27° from 46° normal
🌞 Normal high: 69°F 🌑 Normal low: 46°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

First & Last Dates — Rapid City Downtown

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)
196 days
Longest growing season
1940
111 days
Shortest growing season
1949
154 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 26

# Temp Date
🏆 96°F September 26, 2024
2 93°F September 26, 2014
3 92°F September 26, 1963
4 92°F September 26, 1956
5 92°F September 26, 1898
6 92°F September 26, 1892
7 91°F September 26, 1914
8 90°F September 26, 2021
9 90°F September 26, 1952
10 89°F September 26, 2015

Top 5 Record Lows — September 26

# Temp Date
🥶 19°F September 26, 1934
2 22°F September 26, 1942
3 28°F September 26, 1927
4 29°F September 26, 1900
5 30°F September 26, 1965
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

Days ≥ 90°F Per Year

1888–2026
49
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

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 (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")

This Year — 2026

How Rapid City Downtown is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

185 of 267 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

12.64"
2026 YTD
Normal: 17.44"
-4.80"
1.50"
September so far
September normal: 1.40"
+0.10"
2
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Rapid City Downtown is 4.80" behind the normal pace

Period Review — Jun 27 – Sep 25, 2026

Any window, evaluated against every other year on record — 91 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
75.1°F
Average temperature
2nd-warmest of 115
+4.9°
vs. average
Normal: 70.1°F (1991–2020)

Average Temperature by Year — Jun 27 – Sep 25

1888–2026 · 2026 highlighted · trend +0.26° per decade (warming since 1888)

Precipitation by Year — Jun 27 – Sep 25

1888–2025 · 2026 highlighted · trend +0.09" per decade (wetter since 1888)

Warmest Jun 27 – Sep 25 on Record

# Year Avg Temp
1 1936 75.7°F
2 2026 75.1°F
3 2022 74.3°F
4 2012 73.8°F
5 2024 73.8°F
6 2021 73.4°F
7 1937 73.0°F
8 1955 72.7°F
9 1960 72.6°F
10 1939 72.6°F

Coolest Jun 27 – Sep 25 on Record

# Year Avg Temp
1 1915 63.1°F
2 1903 64.8°F
3 1912 65.0°F
4 1927 65.5°F
5 1918 65.6°F
6 1907 65.6°F
7 1950 66.0°F
8 1902 66.0°F
9 1911 66.1°F
10 1965 66.3°F
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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