Trenton weather in September: Trenton, New Jersey: normal highs, lows, rain and records for September
Trenton in September has a normal high of 77°F and a normal low of 58°F, a daily mean of 67°F, falling from 82°F on the 1st to 72°F by the 30th. Measurable precipitation falls on 9 days in a normal September, 4.05 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 25°C and low of 14°C, 103 mm of precipitation in September.
- NOAA stationTrenton-Mercer Airport
- Station IDUSW00014792
- Location40.28°N 74.82°W
- Elevation184 ft (56 m)
- From the center5 miles
- Population91,193
- Jan 40° 24°
- Feb 43° 26°
- Mar 51° 33°
- Apr 63° 42°
- May 72° 52°
- Jun 81° 61°
- Jul 86° 67°
- Aug 84° 65°
- Sep 77° 58°
- Oct 66° 46°
- Nov 55° 36°
- Dec 44° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Trenton in September?
The normal high is 77°F and the normal low 58°F, for a daily mean of 67.4°F. September is 7.0°F cooler than August and 11.7°F warmer than October. September is the 4th warmest month of the year in Trenton and the 4th wettest. Across the month the normal high falls 10°F, from 82°F on September 1 to 72°F on September 30. From one year to the next September's mean temperature typically moves about 2.3°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 65°F and 70°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 32%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 82°F | 62°F | 29% | 19% |
| September 8 | 80°F | 60°F | 28% | 19% |
| September 15 | 78°F | 58°F | 29% | 19% |
| September 22 | 75°F | 56°F | 30% | 19% |
| September 30 | 72°F | 52°F | 32% | 20% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 82°F | 62°F | 29% | 19% | 13 h 10 min |
| September 2 | 81°F | 62°F | 28% | 19% | 13 h 10 min |
| September 3 | 81°F | 62°F | 28% | 19% | 13 h |
| September 4 | 81°F | 61°F | 28% | 19% | 13 h |
| September 5 | 81°F | 61°F | 28% | 19% | 13 h |
| September 6 | 80°F | 61°F | 28% | 19% | 12 h 50 min |
| September 7 | 80°F | 61°F | 28% | 19% | 12 h 50 min |
| September 8 | 80°F | 60°F | 28% | 19% | 12 h 50 min |
| September 9 | 80°F | 60°F | 28% | 19% | 12 h 50 min |
| September 10 | 79°F | 60°F | 28% | 19% | 12 h 40 min |
| September 11 | 79°F | 59°F | 28% | 19% | 12 h 40 min |
| September 12 | 79°F | 59°F | 28% | 19% | 12 h 40 min |
| September 13 | 78°F | 59°F | 29% | 19% | 12 h 40 min |
| September 14 | 78°F | 59°F | 29% | 19% | 12 h 30 min |
| September 15 | 78°F | 58°F | 29% | 19% | 12 h 30 min |
| September 16 | 77°F | 58°F | 29% | 19% | 12 h 30 min |
| September 17 | 77°F | 58°F | 29% | 19% | 12 h 30 min |
| September 18 | 77°F | 57°F | 29% | 19% | 12 h 20 min |
| September 19 | 76°F | 57°F | 29% | 19% | 12 h 20 min |
| September 20 | 76°F | 56°F | 30% | 19% | 12 h 20 min |
| September 21 | 75°F | 56°F | 30% | 19% | 12 h 20 min |
| September 22 | 75°F | 56°F | 30% | 19% | 12 h 10 min |
| September 23 | 75°F | 55°F | 30% | 19% | 12 h 10 min |
| September 24 | 74°F | 55°F | 31% | 19% | 12 h 10 min |
| September 25 | 74°F | 55°F | 31% | 19% | 12 h 10 min |
| September 26 | 73°F | 54°F | 31% | 20% | 12 h |
| September 27 | 73°F | 54°F | 31% | 20% | 12 h |
| September 28 | 73°F | 53°F | 31% | 20% | 12 h |
| September 29 | 72°F | 53°F | 32% | 20% | 11 h 50 min |
| September 30 | 72°F | 52°F | 32% | 20% | 11 h 50 min |
- Normal high
- 77°FSeptember average
- Normal low
- 58°FSeptember average
- Precipitation
- 4.05 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 2
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 26
- Days at 80°F or more
- 12
- Sunshine
- 76%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014792; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Trenton in September?
On a given September day the chance of 0.01 inch or more is 29% on average, highest around September 30 (32%). In all, 4.05 in falls on 9 days of a normal September, 1 of them with an inch or more.
In a normal September in Trenton, 2 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014792.
What are the records for September in Trenton?
The warmest September temperature on Trenton's official record (since 1865) is 101°F, on September 10, 1983; the coldest is 34°F, on September 25, 1997. The wettest September brought 11.22 in (1999).
The September mean against the 1991-2020 normal of 67.4°F: 2021 68.2°F (+0.8), 2022 67.5°F (+0.1), 2023 67.9°F (+0.5), 2024 66.8°F (−0.6), 2025 69.1°F (+1.7), 2026 68.6°F (+1.2). 5 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 68.2°F | +0.8°F | 7.79 in |
| 2022 | 67.5°F | +0.1°F | 2.43 in |
| 2023 | 67.9°F | +0.5°F | 6.65 in |
| 2024 | 66.8°F | −0.6°F | 0.43 in |
| 2025 | 69.1°F | +1.7°F | 1.89 in |
| 2026 | 68.6°F | +1.2°F | 5.59 in |
Source: records: ACIS, NWS threaded record TTNthr; recent months: ACIS, station USW00014792. Records and recent months use complete months only.
How does September in Trenton compare across New Jersey?
Across the 33 places PlainClimate covers in New Jersey, September normal highs run from 74°F in Andover to 80°F in Belleplain; Trenton's is 77°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.