Portland weather in September: Portland, Oregon: normal highs, lows, rain and records for September
Portland in September has a normal high of 77°F and a normal low of 54°F, a daily mean of 65°F, falling from 80°F on the 1st to 72°F by the 30th. Measurable precipitation falls on 7 days in a normal September, 1.52 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 25°C and low of 12°C, 39 mm of precipitation in September.
- NOAA stationPortland International Airport
- Station IDUSW00024229
- Location45.59°N 122.60°W
- Elevation19 ft (6 m)
- From the center4 miles
- Population635,749
- Jan 48° 36°
- Feb 52° 37°
- Mar 57° 40°
- Apr 62° 44°
- May 69° 49°
- Jun 74° 54°
- Jul 82° 59°
- Aug 82° 59°
- Sep 77° 54°
- Oct 64° 47°
- Nov 54° 41°
- Dec 47° 36°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Portland in September?
The normal high is 77°F and the normal low 54°F, for a daily mean of 65.4°F. September is 5.2°F cooler than August and 9.8°F warmer than October. September is the 3rd warmest month of the year in Portland and the 10th wettest. Across the month the normal high falls 8°F, from 80°F on September 1 to 72°F on September 30. From one year to the next September's mean temperature typically moves about 1.8°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 64°F and 67°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 | 80°F | 57°F | 17% | 8% |
| September 8 | 79°F | 56°F | 20% | 10% |
| September 15 | 77°F | 54°F | 24% | 12% |
| September 22 | 75°F | 53°F | 27% | 15% |
| September 30 | 72°F | 51°F | 32% | 18% |
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 | 80°F | 57°F | 17% | 8% | 13 h 20 min |
| September 2 | 80°F | 57°F | 18% | 8% | 13 h 20 min |
| September 3 | 80°F | 57°F | 18% | 9% | 13 h 10 min |
| September 4 | 80°F | 57°F | 18% | 9% | 13 h 10 min |
| September 5 | 80°F | 56°F | 19% | 9% | 13 h 10 min |
| September 6 | 79°F | 56°F | 19% | 9% | 13 h 10 min |
| September 7 | 79°F | 56°F | 20% | 10% | 13 h |
| September 8 | 79°F | 56°F | 20% | 10% | 13 h |
| September 9 | 79°F | 56°F | 20% | 10% | 13 h |
| September 10 | 79°F | 55°F | 21% | 11% | 12 h 50 min |
| September 11 | 78°F | 55°F | 21% | 11% | 12 h 50 min |
| September 12 | 78°F | 55°F | 22% | 11% | 12 h 50 min |
| September 13 | 78°F | 55°F | 22% | 12% | 12 h 40 min |
| September 14 | 78°F | 55°F | 23% | 12% | 12 h 40 min |
| September 15 | 77°F | 54°F | 24% | 12% | 12 h 40 min |
| September 16 | 77°F | 54°F | 24% | 13% | 12 h 30 min |
| September 17 | 77°F | 54°F | 25% | 13% | 12 h 30 min |
| September 18 | 76°F | 54°F | 25% | 13% | 12 h 30 min |
| September 19 | 76°F | 53°F | 26% | 14% | 12 h 20 min |
| September 20 | 76°F | 53°F | 26% | 14% | 12 h 20 min |
| September 21 | 75°F | 53°F | 26% | 14% | 12 h 20 min |
| September 22 | 75°F | 53°F | 27% | 15% | 12 h 10 min |
| September 23 | 75°F | 53°F | 28% | 15% | 12 h 10 min |
| September 24 | 74°F | 52°F | 28% | 15% | 12 h 10 min |
| September 25 | 74°F | 52°F | 29% | 16% | 12 h 10 min |
| September 26 | 73°F | 52°F | 29% | 16% | 12 h |
| September 27 | 73°F | 51°F | 30% | 17% | 12 h |
| September 28 | 73°F | 51°F | 30% | 17% | 12 h |
| September 29 | 72°F | 51°F | 31% | 17% | 11 h 50 min |
| September 30 | 72°F | 51°F | 32% | 18% | 11 h 50 min |
- Normal high
- 77°FSeptember average
- Normal low
- 54°FSeptember average
- Precipitation
- 1.52 inmonth total
- Days with precipitation
- 70.01 inch or more
- Days at 90°F or more
- 2
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 23
- Days at 80°F or more
- 11
- Sunshine
- 78%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024229; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Portland in September?
On a given September day the chance of 0.01 inch or more is 24% on average, highest around September 30 (32%). In all, 1.52 in falls on 7 days of a normal September.
In a normal September in Portland, 2 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024229.
How humid and windy is Portland in September?
At 3 p.m. the normal temperature is 70°F with 47% relative humidity and a dew point of 49°F; at 6 a.m. it is 53°F with 88% humidity. The wind averages 5.8 mph, most often from the west-northwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 53°F | 49°F | 88% | 4.4 mph | 35% |
| 9 a.m. | 58°F | 50°F | 76% | 5.2 mph | 34% |
| noon | 65°F | 50°F | 57% | 7.3 mph | 46% |
| 3 p.m. | 70°F | 49°F | 47% | 8.1 mph | 44% |
| 6 p.m. | 66°F | 50°F | 56% | 7.3 mph | 46% |
| 9 p.m. | 60°F | 51°F | 71% | 5.4 mph | 57% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024229. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Portland?
The warmest September temperature on Portland's official record (since 1940) is 105°F, on September 2, 1988; the coldest is 34°F, on September 22, 1961. The wettest September brought 5.62 in (2013).
The September mean against the 1991-2020 normal of 65.4°F: 2021 66.4°F (+1.0), 2022 69.5°F (+4.1), 2023 66.4°F (+1.0), 2024 67.7°F (+2.3), 2025 67.7°F (+2.3), 2026 63.5°F (−1.9). 5 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 66.4°F | +1.0°F | 3.76 in |
| 2022 | 69.5°F | +4.1°F | 0.31 in |
| 2023 | 66.4°F | +1.0°F | 1.25 in |
| 2024 | 67.7°F | +2.3°F | 0.74 in |
| 2025 | 67.7°F | +2.3°F | 1.06 in |
| 2026 | 63.5°F | −1.9°F | 0.93 in |
Source: records: ACIS, NWS threaded record PDXthr; recent months: ACIS, station USW00024229. Records and recent months use complete months only.
How does September in Portland compare across Oregon?
Across the 105 places PlainClimate covers in Oregon, September normal highs run from 64°F in Newport to 87°F in Cave Junction; Portland's is 77°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.