Portland, ME

Maine · Records since 1874–2026

☀️ 74°F
Currently in Portland
As of 2:30 PM EDT

Records for September 11

🔥 Record High

95°F

September 11, 1983

+22° from 73° normal

❄ Record Low

35°F

September 11, 1963

-19° from 54° normal
🌞 Normal high: 73°F 🌑 Normal low: 54°F 1991–2020 normals

All-Time Records — Portland

🔥
103°F
Hottest Day Ever
Aug 2, 1975
❄
-39°F
Coldest Day Ever
Feb 16, 1943
🌧
11.74"
Wettest Day Ever
Oct 21, 1996
☃
22.3"
Most Snow in One Day
Dec 17, 1970

First & Last Dates — Portland

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)
222 days
Longest growing season
1878
109 days
Shortest growing season
1961
162 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 95°F September 11, 1983
2 95°F September 11, 1931
3 93°F September 11, 2013
4 91°F September 11, 1961
5 89°F September 11, 1964
6 88°F September 11, 1989
7 87°F September 11, 1908
8 85°F September 11, 2019
9 85°F September 11, 1947
10 84°F September 11, 1982

Top 5 Record Lows — September 11

# Temp Date
🥶 35°F September 11, 1963
2 36°F September 11, 1953
3 37°F September 11, 1975
4 38°F September 11, 1995
5 39°F September 11, 1949
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 1874–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Portland

threshold: 86°F (90th percentile of historical Jun–Aug highs)
3.7
Avg heat wave length
days (historical)
93°
Avg peak temp
during heat waves
4
Dangerous nights 2026
Overnights ≥ 70°F
1
Heat waves 2026
so far

Days ≥ 90°F Per Year

1874–2026
7
2026 so far
5
Avg/year 1970–2025
6
Avg/year (last 10 complete)
16
Most in a year (1955)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Portland

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 6, 1988 – Jul 13, 1988 8 93°F (Jul 11) 90°F 65°F
2 Aug 12, 2002 – Aug 19, 2002 8 93°F (Aug 14) 89°F 66°F
3 Jul 15, 1991 – Jul 21, 1991 7 96°F (Jul 21) 91°F 65°F
4 Aug 5, 1876 – Aug 11, 1876 7 95°F (Aug 7) 90°F 68°F
5 Jul 13, 1952 – Jul 19, 1952 7 94°F (Jul 14) 91°F 62°F
6 Jul 23, 1970 – Jul 29, 1970 7 93°F (Jul 24) 90°F 64°F
7 Jul 24, 2020 – Jul 30, 2020 7 93°F (Jul 27) 90°F 70°F
8 Aug 11, 1944 – Aug 16, 1944 6 99°F (Aug 11) 95°F 68°F
9 Jul 16, 1977 – Jul 21, 1977 6 99°F (Jul 21) 92°F 65°F
10 Jul 6, 1993 – Jul 11, 1993 6 98°F (Jul 10) 92°F 67°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

48
2026 total
above-normal nights
34.0
Avg / summer
1970–2020
63
Most in a summer
2020

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 (1871–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1871, annual totals have trended +0.51" per decade, about +7.8" 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 Portland is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

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

Precipitation, Year to Date

27.22"
2026 YTD
Normal: 31.46"
-4.24"
0.48"
September so far
September normal: 3.77"
-3.29"
8
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Portland is 4.24" 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)
67.8°F
Average temperature
27th-warmest of 153
+0.8°
vs. average
Normal: 66.9°F (1991–2020)
2.10"
Precipitation
57th-driest of 153
-1.49"
vs. average
Normal: 3.59" · 58% of normal

Average Temperature by Year — Aug 11 – Sep 10

1874–2026 · 2026 highlighted · trend +0.14° per decade (warming since 1874)

Precipitation by Year — Aug 11 – Sep 10

1871–2026 · 2026 highlighted · trend +0.01" per decade (wetter since 1871)

Warmest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 2015 71.0°F
2 2016 71.0°F
3 1875 70.6°F
4 1937 70.2°F
5 2021 69.8°F
6 1969 69.7°F
7 2020 69.5°F
8 1959 69.2°F
9 1884 69.0°F
10 2018 69.0°F

Coolest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 1963 60.3°F
2 1941 61.6°F
3 1885 61.8°F
4 1964 61.8°F
5 1946 61.9°F
6 1957 61.9°F
7 1903 62.0°F
8 1904 62.2°F
9 1954 62.3°F
10 1923 62.4°F

Wettest Aug 11 – Sep 10 on Record

# Year Total
1 1991 10.44"
2 1896 8.65"
3 2014 8.19"
4 1892 7.28"
5 2004 7.09"
6 2008 7.08"
7 2022 6.76"
8 1887 6.48"
9 1966 6.48"
10 1872 6.17"

Driest Aug 11 – Sep 10 on Record

# Year Total
1 1883 0.32"
2 1925 0.37"
3 2007 0.52"
4 1960 0.69"
5 1995 0.80"
6 1968 0.91"
7 1948 0.91"
8 2024 0.93"
9 1921 0.98"
10 1977 1.00"
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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