Denver, CO

Colorado · Records since 1872–2026

☁️ 89°F Feels like 83°
Currently in Denver
As of 12:15 PM MDT

Records for September 11

🔥 Record High

97°F

September 11, 2021

+15° from 82° normal

❄ Record Low

32°F

September 11, 1898

-20° from 52° normal
🌞 Normal high: 82°F 🌑 Normal low: 52°F 1991–2020 normals

All-Time Records — Denver

🔥
105°F
Hottest Day Ever
Jun 28, 2018
❄
-29°F
Coldest Day Ever
Jan 9, 1875
🌧
6.50"
Wettest Day Ever
May 22, 1876
☃
23.6"
Most Snow in One Day
Dec 24, 1982

First & Last Dates — Denver

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)
200 days
Longest growing season
1940
110 days
Shortest growing season
1951
147 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 97°F September 11, 2021
2 93°F September 11, 2018
3 92°F September 11, 1951
4 90°F September 11, 2016
5 90°F September 11, 2012
6 90°F September 11, 2005
7 90°F September 11, 1993
8 90°F September 11, 1992
9 90°F September 11, 1970
10 90°F September 11, 1962

Top 5 Record Lows — September 11

# Temp Date
🥶 32°F September 11, 1898
2 34°F September 11, 2014
3 34°F September 11, 1878
4 36°F September 11, 1974
5 36°F September 11, 1892
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 1872–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Denver

threshold: 94°F (90th percentile of historical Jun–Aug highs)
4.1
Avg heat wave length
days (historical)
98°
Avg peak temp
during heat waves
4
Dangerous nights 2026
Overnights ≥ 70°F
6
Heat waves 2026
so far

Days ≥ 90°F Per Year

1872–2026
64
2026 so far
32
Avg/year 1970–2025
56
Avg/year (last 10 complete)
75
Most in a year (2020)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Denver

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jun 22, 2012 – Jul 5, 2012 14 105°F (Jun 25) 100°F 65°F
2 Jul 2, 1874 – Jul 13, 1874 12 102°F (Jul 4) 98°F 62°F
3 Jul 12, 2022 – Jul 23, 2022 12 100°F (Jul 18) 97°F 65°F
4 Jun 23, 1990 – Jul 3, 1990 11 102°F (Jun 27) 99°F 63°F
5 Jul 6, 2005 – Jul 16, 2005 11 102°F (Jul 16) 97°F 62°F
6 Jul 27, 2024 – Aug 6, 2024 11 102°F (Aug 4) 98°F 63°F
7 Jun 30, 1989 – Jul 9, 1989 10 103°F (Jul 8) 99°F 62°F
8 Jun 29, 2001 – Jul 6, 2001 8 101°F (Jul 1) 97°F 64°F
9 Jul 18, 2016 – Jul 25, 2016 8 99°F (Jul 23) 96°F 63°F
10 Jul 6, 2020 – Jul 13, 2020 8 99°F (Jul 7) 97°F 62°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

64
2026 total
above-normal nights
39.5
Avg / summer
1970–2020
77
Most in a summer
1934

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 (1872–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1872, annual totals have trended +0.04" per decade, about +0.6" 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 Denver is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

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

Precipitation, Year to Date

7.24"
2026 YTD
Normal: 11.59"
-4.35"
0.00"
September so far
September normal: 1.35"
-1.35"
0
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Denver is 4.35" 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)
75.0°F
Average temperature
2nd-warmest of 155
+4.0°
vs. average
Normal: 71.0°F (1991–2020)
1.59"
Precipitation
52nd-wettest of 155
+0.36"
vs. average
Normal: 1.23" · 129% of normal

Average Temperature by Year — Aug 11 – Sep 10

1872–2026 · 2026 highlighted · trend +0.21° per decade (warming since 1872)

Precipitation by Year — Aug 11 – Sep 10

1872–2026 · 2026 highlighted · trend -0.01" per decade (drier since 1872)

Warmest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 2013 75.6°F
2 2026 75.0°F
3 2019 74.9°F
4 2023 74.7°F
5 2024 74.6°F
6 2021 74.5°F
7 1937 74.3°F
8 2022 74.3°F
9 1995 73.8°F
10 1994 73.8°F

Coolest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 1920 63.9°F
2 1885 65.0°F
3 1968 65.1°F
4 1918 65.5°F
5 1992 65.8°F
6 2008 65.8°F
7 2004 65.9°F
8 1915 66.0°F
9 1890 66.4°F
10 1923 66.9°F

Wettest Aug 11 – Sep 10 on Record

# Year Total
1 1972 4.10"
2 1909 3.82"
3 2004 3.67"
4 1979 3.63"
5 1921 3.15"
6 1887 3.06"
7 1938 2.94"
8 1961 2.89"
9 2013 2.75"
10 2000 2.72"

Driest Aug 11 – Sep 10 on Record

# Year Total
1 2010 0.02"
2 1889 0.04"
3 1928 0.05"
4 1917 0.05"
5 1978 0.08"
6 1897 0.09"
7 1899 0.10"
8 1959 0.13"
9 1948 0.13"
10 2017 0.15"
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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