Philadelphia Center City, PA

Pennsylvania · Records since 1940–2026

☁️ 81°F Feels like 84°
Currently in Philadelphia Center City
As of 2:30 PM EDT

Records for September 11

🔥 Record High

101°F

September 11, 1983

+19° from 82° normal

❄ Record Low

52°F

September 11, 1993

-12° from 64° normal
🌞 Normal high: 82°F 🌑 Normal low: 64°F 1991–2020 normals

All-Time Records — Philadelphia Center City

🔥
107°F
Hottest Day Ever
Jul 3, 1966
❄
-5°F
Coldest Day Ever
Jan 19, 1994
🌧
7.50"
Wettest Day Ever
Sep 28, 2004
☃
24.0"
Most Snow in One Day
Jan 8, 1996

First & Last Dates — Philadelphia Center City

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)
274 days
Longest growing season
1998
209 days
Shortest growing season
1976
236 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 101°F September 11, 1983
2 92°F September 11, 1964
3 91°F September 11, 1961
4 89°F September 11, 1989
5 88°F September 11, 2013
6 88°F September 11, 2005
7 88°F September 11, 1982
8 87°F September 11, 1947
9 86°F September 11, 1990
10 86°F September 11, 1973

Top 5 Record Lows — September 11

# Temp Date
🥶 52°F September 11, 1993
2 52°F September 11, 1967
3 53°F September 11, 1994
4 54°F September 11, 2017
5 54°F September 11, 1995
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 1940–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Philadelphia Center City

threshold: 94°F (90th percentile of historical Jun–Aug highs)
4.1
Avg heat wave length
days (historical)
99°
Avg peak temp
during heat waves
59
Dangerous nights 2026
Overnights ≥ 70°F
3
Heat waves 2026
so far

Days ≥ 90°F Per Year

1940–2026
43
2026 so far
30
Avg/year 1970–2025
45
Avg/year (last 10 complete)
73
Most in a year (2005)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Philadelphia Center City

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 28, 2002 – Aug 5, 2002 9 102°F (Aug 2) 98°F 78°F
2 Aug 11, 2002 – Aug 19, 2002 9 102°F (Aug 13) 98°F 78°F
3 Aug 27, 1973 – Sep 3, 1973 8 102°F (Aug 28) 98°F 79°F
4 Aug 27, 1953 – Sep 3, 1953 8 100°F (Aug 30) 98°F 78°F
5 Jun 30, 2018 – Jul 6, 2018 7 101°F (Jul 3) 98°F 78°F
6 Jun 7, 1984 – Jun 13, 1984 7 99°F (Jun 9) 98°F 76°F
7 Jul 19, 2022 – Jul 25, 2022 7 99°F (Jul 24) 97°F 79°F
8 Jul 13, 1997 – Jul 18, 1997 6 100°F (Jul 15) 98°F 78°F
9 Jul 16, 2013 – Jul 21, 2013 6 99°F (Jul 19) 97°F 80°F
10 Aug 12, 2016 – Aug 17, 2016 6 99°F (Aug 13) 97°F 79°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

50
2026 total
above-normal nights
42.0
Avg / summer
1970–2020
66
Most in a summer
2005

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 (1940–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1940, annual totals have trended +0.29" per decade, about +2.4" 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 Philadelphia Center City is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

109 of 234 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

11.03"
2026 YTD
Normal: 35.74"
-24.71"
0.00"
September so far
September normal: 4.88"
-4.88"
5
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Philadelphia Center City is 24.71" behind the normal pace

Period Review — Jun 12 – Sep 10, 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)
79.8°F
Average temperature
8th-warmest of 85
+1.6°
vs. average
Normal: 78.3°F (1991–2020)

Average Temperature by Year — Jun 12 – Sep 10

1941–2026 · 2026 highlighted · trend +0.46° per decade (warming since 1941)

Precipitation by Year — Jun 12 – Sep 10

1941–2015 · 2026 highlighted · trend +0.49" per decade (wetter since 1941)

Warmest Jun 12 – Sep 10 on Record

# Year Avg Temp
1 2005 81.8°F
2 2010 80.5°F
3 2002 80.2°F
4 2016 80.2°F
5 2018 80.1°F
6 1983 80.0°F
7 2022 79.9°F
8 2026 79.8°F
9 2024 79.6°F
10 1973 79.5°F

Coolest Jun 12 – Sep 10 on Record

# Year Avg Temp
1 1946 73.5°F
2 1992 73.5°F
3 1962 73.6°F
4 1979 73.8°F
5 1950 73.9°F
6 1958 74.2°F
7 1978 74.2°F
8 1974 74.4°F
9 1982 74.4°F
10 1956 74.6°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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