Duluth weather in September: Duluth, Minnesota: normal highs, lows, rain and records for September
Duluth in September has a normal high of 67°F and a normal low of 47°F, a daily mean of 57°F, falling from 73°F on the 1st to 61°F by the 30th. Measurable precipitation falls on 12 days in a normal September, 3.48 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 20°C and low of 8°C, 88 mm of precipitation and 0 cm of snow in September.
- NOAA stationDuluth International Airport
- Station IDUSW00014913
- Location46.84°N 92.21°W
- Elevation1,428 ft (435 m)
- From the center6 miles
- Population87,986
- Jan 20° 2°
- Feb 25° 6°
- Mar 36° 18°
- Apr 49° 30°
- May 63° 41°
- Jun 72° 50°
- Jul 78° 56°
- Aug 76° 55°
- Sep 67° 47°
- Oct 53° 36°
- Nov 37° 23°
- Dec 25° 10°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Duluth in September?
The normal high is 67°F and the normal low 47°F, for a daily mean of 57.2°F. September is 8.3°F cooler than August and 13.1°F warmer than October. September is the 4th warmest month of the year in Duluth and the 4th wettest. Across the month the normal high falls 12°F, from 73°F on September 1 to 61°F on September 30. From one year to the next September's mean temperature typically moves about 2.8°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 54°F and 60°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 39%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 73°F | 52°F | 36% | 21% |
| September 8 | 70°F | 50°F | 37% | 22% |
| September 15 | 68°F | 48°F | 38% | 22% |
| September 22 | 65°F | 45°F | 39% | 22% |
| September 30 | 61°F | 42°F | 39% | 22% |
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 | 73°F | 52°F | 36% | 21% | 13 h 20 min |
| September 2 | 72°F | 52°F | 36% | 22% | 13 h 20 min |
| September 3 | 72°F | 52°F | 36% | 22% | 13 h 20 min |
| September 4 | 72°F | 51°F | 36% | 22% | 13 h 10 min |
| September 5 | 71°F | 51°F | 36% | 22% | 13 h 10 min |
| September 6 | 71°F | 51°F | 37% | 22% | 13 h 10 min |
| September 7 | 71°F | 50°F | 37% | 22% | 13 h |
| September 8 | 70°F | 50°F | 37% | 22% | 13 h |
| September 9 | 70°F | 50°F | 37% | 22% | 13 h |
| September 10 | 70°F | 49°F | 37% | 22% | 12 h 50 min |
| September 11 | 69°F | 49°F | 37% | 22% | 12 h 50 min |
| September 12 | 69°F | 49°F | 37% | 22% | 12 h 50 min |
| September 13 | 69°F | 48°F | 37% | 22% | 12 h 40 min |
| September 14 | 68°F | 48°F | 38% | 22% | 12 h 40 min |
| September 15 | 68°F | 48°F | 38% | 22% | 12 h 40 min |
| September 16 | 67°F | 47°F | 38% | 22% | 12 h 40 min |
| September 17 | 67°F | 47°F | 38% | 22% | 12 h 30 min |
| September 18 | 67°F | 47°F | 38% | 22% | 12 h 30 min |
| September 19 | 66°F | 46°F | 38% | 22% | 12 h 30 min |
| September 20 | 66°F | 46°F | 39% | 22% | 12 h 20 min |
| September 21 | 65°F | 45°F | 39% | 22% | 12 h 20 min |
| September 22 | 65°F | 45°F | 39% | 22% | 12 h 20 min |
| September 23 | 64°F | 45°F | 39% | 22% | 12 h 10 min |
| September 24 | 64°F | 44°F | 39% | 22% | 12 h 10 min |
| September 25 | 63°F | 44°F | 39% | 22% | 12 h 10 min |
| September 26 | 63°F | 43°F | 39% | 22% | 12 h |
| September 27 | 62°F | 43°F | 39% | 22% | 12 h |
| September 28 | 62°F | 43°F | 39% | 22% | 12 h |
| September 29 | 61°F | 42°F | 39% | 22% | 11 h 50 min |
| September 30 | 61°F | 42°F | 39% | 22% | 11 h 50 min |
- Normal high
- 67°FSeptember average
- Normal low
- 47°FSeptember average
- Precipitation
- 3.48 inmonth total
- Days with precipitation
- 120.01 inch or more
- Snowfall
- 0.1 inmonth total
- Nights at 32°F or colder
- 1
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 11
- Days at 80°F or more
- 2
- Sunshine
- 72%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014913; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Duluth in September?
On a given September day the chance of 0.01 inch or more is 38% on average, highest around September 26 (39%). In all, 3.48 in falls on 12 days of a normal September, 1 of them with an inch or more.
In a normal September in Duluth, 1 nights fall to freezing and snowfall averages 0.1 inches.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014913.
How humid and windy is Duluth in September?
At 3 p.m. the normal temperature is 57°F with 56% relative humidity and a dew point of 41°F; at 6 a.m. it is 45°F with 85% humidity. The wind averages 10.0 mph, most often from the west in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 45°F | 40°F | 85% | 8.7 mph | 43% |
| 9 a.m. | 50°F | 42°F | 73% | 11.2 mph | 48% |
| noon | 56°F | 42°F | 59% | 12.5 mph | 38% |
| 3 p.m. | 57°F | 41°F | 56% | 12.1 mph | 48% |
| 6 p.m. | 52°F | 42°F | 67% | 9.2 mph | 47% |
| 9 p.m. | 49°F | 42°F | 77% | 9.0 mph | 58% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014913. 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 Duluth?
The warmest September temperature on Duluth's official record (since 1874) is 97°F, on September 3, 2023; the coldest is 23°F, on September 20, 1962. The wettest September brought 11.52 in (1881); the snowiest, 2.4 inches (1991).
The September mean against the 1991-2020 normal of 57.2°F: 2021 60.2°F (+3.0), 2022 58.6°F (+1.4), 2023 61.9°F (+4.7), 2024 64.3°F (+7.1), 2025 59.1°F (+1.9), 2026 59.5°F (+2.3). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.2°F | +3.0°F | 3.60 in |
| 2022 | 58.6°F | +1.4°F | 2.73 in |
| 2023 | 61.9°F | +4.7°F | 10.36 in |
| 2024 | 64.3°F | +7.1°F | 0.31 in |
| 2025 | 59.1°F | +1.9°F | 2.53 in |
| 2026 | 59.5°F | +2.3°F | 3.45 in |
Source: records: ACIS, NWS threaded record DLHthr; recent months: ACIS, station USW00014913. Records and recent months use complete months only.
How does September in Duluth compare across Minnesota?
Across the 129 places PlainClimate covers in Minnesota, September normal highs run from 62°F in Lutsen to 76°F in Milan; Duluth's is 67°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.