Historical climate averages in Philadelphia for September
United States · 1984–2025 · 33 daily observations
A month-level reference built from observed daily highs, lows, and precipitation values. Use it to see how September fits into Philadelphia's annual pattern, then jump to nearby months below.
Average High
26.3°C
Average Low
17.0°C
Record High
31.6°C
Record Low
13.1°C
Average Daily Precipitation
2.4mm
Data Coverage
1984–2025 (33 obs)
September in context
September in Philadelphia is the 4th warmest month by average daytime high. Average highs reach 26.3°C and average lows settle near 17.0°C.
the 8th wettest month by average daily precipitation. Average daily precipitation is 2.4mm, versus 4.3mm in May, the wettest month.
This snapshot is built from 33 daily observations collected between 1984 and 2025. Record highs and lows mark the single hottest and coldest daily readings in the archive for this month.
Relative to the full year
- Daytime highs: +8.5°C vs city-wide monthly average
- Nighttime lows: +8.2°C vs city-wide monthly average
- Daily precipitation: -0.4mm vs city-wide monthly average
Archive quality
- Coverage: 1984–2025 (33 obs)
- Temperature span: 18.5°C between record low and high
- Driest month benchmark: August at 0.7mm
How this summary is calculated
PastWeather groups all recorded days for September, then calculates the average daytime high, average nighttime low, and average daily precipitation value for that month. The cards above stay tied to observed data rather than travel copy or generic climate descriptions.
Average high / low
Mean daily maximum and minimum temperatures across every recorded September day in the archive.
Record extremes
The single hottest and coldest daily readings observed during this month, useful for understanding outlier risk.
Precipitation note
Precipitation is shown as an average daily value for this month, which helps compare wetter and drier parts of the year on the same basis.
Explore another month
Move month by month or jump straight to the warmest, coldest, or wettest part of the year for Philadelphia.