Duluth Harbor Stn, MN Climate: Temperature by Month
Average temperature and precipitation from NOAA NCEI 1991–2020 normals →, with a derived climate comfort score
30-year climate normals (1991-2020) from Duluth Harbor Stn's primary NOAA station, DULUTH HARBOR STN.
The climate verdict for Duluth Harbor Stn
Duluth Harbor Stn, Minnesota has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 41°F. August is the warmest month at 67°F and January the coldest at 13°F.
- 41°F
- annual average temperature (NOAA normal)
- 151 days
- frost-free growing season
Duluth Harbor Stn: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00212246 · Duluth Harbor Stn, MN 41°F mean
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-UNK · SWING-WIDE · COMF-UNK · LOAD-HEAT · STN-1 · BOOK-PART
- TEMP-COOL 41°F
- RANK-COOL #480
- PHOTO-FINISH ≈ Rice Rsvr Tomah…
- PRCP-UNK Rain n/a
- SWING-WIDE 54°F
- COMF-UNK Comfort n/a
- LOAD-HEAT 9,048 HDD
- STN-1 USC00212246
- BOOK-PART 4/6 fields
Nearest mean-temperature peer: Rice Rsvr Tomahawk-2, WI ( -0.1 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every MN station list.
- Duluth Harbor (this station) 41°F
- Cold Rice Rsvr Tomah…, WI 41°F
- Hot Alberta Ford Fo…, MI 41°F
- Near Caribou, ME 41°F
- Near Prentice, WI 41°F
Duluth Harbor Stn sits in Minnesota, the #3 coldest U.S. state at 42.2°F statewide annual average - see all 50 coldest states ranked by NOAA normals
Climate Living Index · Duluth Harbor Stn
Duluth Harbor Stn: 20/100 · grade F
Duluth Harbor Stn publishes 3 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 3 missing weights rescale to 100.
PlainClimate-derived for Duluth Harbor Stn, not an official NOAA rating. Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 170 calendar days | 32/100 · F |
| Frost-free season | 151 days/year | 26/100 · F |
| Annual temperature balance | 40.8°F · 26.7° from 67.5°F | 6/100 · F |
Duluth Harbor Stn · 2026-08-04 · NOAA NCEI Climate Normals · method .
National standing · heating-led station
Where Duluth Harbor Stn sits across the climate record
Available NOAA 1991–2020 fields for Duluth Harbor Stn are ranked only against stations that publish the same field, missing metrics stay blank rather than estimated.
- Annual temperature
- Cooler than 93%
- Among 6,861 stations, Duluth Harbor Stn sits in the cooler third of annual means.
- Seasonal temperature swing
- Wider than 91%
- Warmest-to-coldest month gap for Duluth Harbor Stn is large versus 6,861 complete station-years.
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 21°F (-6°C) | 4°F (-15°C) | 13°F (-11°C) | N/A | 30.9 | 0.0 |
| February | 26°F (-4°C) | 8°F (-13°C) | 17°F (-8°C) | N/A | 27.8 | 0.0 |
| March | 35°F (2°C) | 19°F (-7°C) | 27°F (-3°C) | N/A | 28.1 | 0.0 |
| April | 45°F (7°C) | 31°F (-1°C) | 38°F (3°C) | N/A | 17.0 | 0.0 |
| May | 56°F (13°C) | 41°F (5°C) | 48°F (9°C) | N/A | 1.9 | 0.0 |
| June | 66°F (19°C) | 49°F (9°C) | 58°F (14°C) | N/A | 0.1 | 0.2 |
| July | 75°F (24°C) | 58°F (14°C) | 66°F (19°C) | N/A | 0.0 | 1.0 |
| August | 74°F (24°C) | 60°F (15°C) | 67°F (19°C) | N/A | 0.1 | 0.9 |
| September | 66°F (19°C) | 51°F (10°C) | 59°F (15°C) | N/A | 0.2 | 0.0 |
| October | 52°F (11°C) | 39°F (4°C) | 45°F (7°C) | N/A | 6.7 | 0.0 |
| November | 39°F (4°C) | 26°F (-3°C) | 32°F (0°C) | N/A | 22.9 | 0.0 |
| December | 27°F (-3°C) | 13°F (-11°C) | 20°F (-7°C) | N/A | 30.0 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 77°F around July 25, short of 90°F on every date, while 170 dates carry a normal low at or below freezing, the coldest 3°F near January 21.
The freezing stretch
The normal low stays at or below 32°F into April 18, then returns to freezing around November 1, covering 170 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
The widest day
July 3 carries the biggest normal gap between afternoon and dawn, 18°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Duluth Harbor Stn.
Where Duluth Harbor Stn Stands Nationally
Among the steadiest day-night climates ranked: even the widest normal daily swing holds to roughly 18°F.
Duluth Harbor Stn earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall
Frost Dates & Growing Season
First Fall Freeze
October 12
50% probability date
Last Spring Freeze
May 14
50% probability date
Growing Season
151 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
9,048
Higher = more heating needed
Cooling Degree Days
259
Higher = more cooling needed
Warmest Month
August
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside MN closest to Duluth Harbor Stn on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (41°F here).
- Morrisville, VT 41°F · 0.0°F off
- Steamboat Springs, CO 41°F · 0.0°F off
- Underwood, ND 41°F · 0.0°F off
- Gordon, WI 41°F · 0.1°F off
Data-derived climate profile
How Duluth Harbor Stn's climate pattern fits together
heating led · mid swing
Duluth Harbor Stn's energy balance leans toward cold weather: 9,048 annual heating degree days against 259 for cooling. Its 54.4°F seasonal range still makes the monthly rows more useful than the annual average alone.
Duluth Harbor Stn's frost-free season lasts about 151 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
August and January mark the typical warm and cold ends of the calendar in Duluth Harbor Stn's middle-range seasonal profile. The measured spread is 54.4°F. The annual average is 41°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
A moisture-range label is withheld because Duluth Harbor Stn's annual precipitation total is unavailable. Monthly source values remain visible where NOAA provides them, and no annual amount is reconstructed from incomplete data.
These labels group NOAA 1991-2020 normals from Duluth Harbor Stn's primary station, so the winter figures are a thirty-year average and not a floor: a single hard season can run well below them. Treat each band as a descriptive range for Duluth Harbor Stn, not an official NOAA class or a year-ahead forecast.
Questions about Duluth Harbor Stn's climate
How cold does Duluth Harbor Stn get in winter? ▼
How much energy does heating and cooling require in Duluth Harbor Stn? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Duluth Harbor Stn's primary station: DULUTH HARBOR STN (USC00212246). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Duluth Harbor Stn; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Duluth Harbor Stn comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.