Copper Harbor Fort Wilkins, Michigan climate: Climate normals at a NOAA weather station
Copper Harbor Fort Wilkins's normal year runs from 11°F January nights to 73°F August afternoons, with 33.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 4.9°C, January lows of −12°C, August highs of 23°C, 842 mm of precipitation a year.
- NOAA stationCopper Harbor Fort Wilkins
- Station IDUSC00201780
- Location47.47°N 87.87°W
- Elevation625 ft (191 m)
On October 23, the normal high in Copper Harbor Fort Wilkins is 49°F and the normal low 36°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Copper Harbor Fort Wilkins.
- Jan 23° 11°
- Feb 25° 10°
- Mar 34° 17°
- Apr 44° 28°
- May 57° 39°
- Jun 67° 46°
- Jul 73° 54°
- Aug 73° 56°
- Sep 66° 50°
- Oct 52° 39°
- Nov 39° 28°
- Dec 29° 18°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Copper Harbor Fort Wilkins each month?
August is the warmest month, with normal highs of 73°F; January the coldest, with normal lows of 11°F. The most precipitation falls in October (3.72 in), the least in March (1.70 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 23°F | 11°F | 17.0°F | 2.24 | – | <1 | 31 | 8 h 50 min |
| February | 25°F | 10°F | 17.4°F | 1.89 | – | <1 | 27 | 10 h 10 min |
| March | 34°F | 17°F | 25.6°F | 1.70 | – | <1 | 28 | 11 h 50 min |
| April | 44°F | 28°F | 36.0°F | 2.68 | – | <1 | 21 | 13 h 30 min |
| May | 57°F | 39°F | 48.0°F | 3.55 | – | <1 | 5 | 15 h |
| June | 67°F | 46°F | 56.7°F | 3.07 | – | <1 | <1 | 16 h |
| July | 73°F | 54°F | 63.8°F | 3.02 | – | 1 | <1 | 15 h 40 min |
| August | 73°F | 56°F | 64.9°F | 2.63 | – | <1 | <1 | 14 h 20 min |
| September | 66°F | 50°F | 58.1°F | 3.71 | – | <1 | <1 | 12 h 40 min |
| October | 52°F | 39°F | 45.4°F | 3.72 | – | <1 | 5 | 11 h |
| November | 39°F | 28°F | 33.4°F | 2.60 | – | <1 | 21 | 9 h 20 min |
| December | 29°F | 18°F | 23.4°F | 2.33 | – | <1 | 30 | 8 h 30 min |
| Year (annual) | 49°F | 33°F | 40.8°F | 33.14 | – | 1 | 167 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −5°C | −12°C | −8.3°C | 57 mm |
| February | −4°C | −12°C | −8.1°C | 48 mm |
| March | 1°C | −8°C | −3.6°C | 43 mm |
| April | 7°C | −2°C | 2.2°C | 68 mm |
| May | 14°C | 4°C | 8.9°C | 90 mm |
| June | 19°C | 8°C | 13.7°C | 78 mm |
| July | 23°C | 12°C | 17.7°C | 77 mm |
| August | 23°C | 13°C | 18.3°C | 67 mm |
| September | 19°C | 10°C | 14.5°C | 94 mm |
| October | 11°C | 4°C | 7.4°C | 94 mm |
| November | 4°C | −2°C | 0.8°C | 66 mm |
| December | −2°C | −8°C | −4.8°C | 59 mm |
NOAA publishes no 1991-2020 snowfall normal for this station, and no record within 25 miles keeps one, so snow is left out here rather than estimated.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00201780; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Copper Harbor Fort Wilkins?
Normal highs sit between 65°F and 85°F in June, July, August and September.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00201780.
When is the last frost at Copper Harbor Fort Wilkins?
In Copper Harbor Fort Wilkins, the last spring frost (32°F) comes after May 20 in half of years and after June 3 in one year in ten; the first autumn frost comes before October 15 in half of years and before September 30 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 201 year in 10 after June 3; 9 in 10 after May 3
- First autumn frost, half of years before
- October 151 year in 10 before September 30; 9 in 10 before October 30
NOAA puts the median frost-free season at 148 days, and the season without a hard freeze (28°F) at 174 days.
A hard freeze (28°F) comes after May 4 in half of springs and before October 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Copper Harbor Fort Wilkins in zone 6a in ZIP code 49918, the nearest ZIP area.
Frost dates for every NOAA station in Michigan · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00201780; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Copper Harbor Fort Wilkins?
In a normal year in Copper Harbor Fort Wilkins, 1 day a year reaches 90°F and 167 nights fall to 32°F or colder.
- Days at 90°F or more
- 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 167a normal year
- Days that stay below freezing
- 84high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00201780.
How sunny is it at Copper Harbor Fort Wilkins?
Over a year 68% of the sunlight that would reach the ground under clear skies gets through the clouds at Copper Harbor Fort Wilkins, 3.4 kWh per square metre a day. July is the sunniest month (78%) and December the cloudiest (41%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 42% | 0.9 |
| February | 51% | 1.7 |
| March | 64% | 3.2 |
| April | 69% | 4.6 |
| May | 72% | 5.5 |
| June | 75% | 6.1 |
| July | 78% | 6.0 |
| August | 78% | 5.2 |
| September | 72% | 3.7 |
| October | 61% | 2.2 |
| November | 48% | 1.1 |
| December | 41% | 0.7 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Copper Harbor Fort Wilkins record?
A normal year at Copper Harbor Fort Wilkins brings 8,959 heating degree days, 67% more than the median U.S. place (5,373), and 176 cooling degree days, 81% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,504 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,488 | 0 |
| February | 1,334 | 0 |
| March | 1,221 | 0 |
| April | 868 | 0 |
| May | 531 | 3 |
| June | 261 | 14 |
| July | 101 | 64 |
| August | 77 | 72 |
| September | 229 | 23 |
| October | 609 | 1 |
| November | 948 | 0 |
| December | 1,291 | 0 |
| Year (annual) | 8,959 | 176 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00201780. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Copper Harbor Fort Wilkins's climate compare?
Copper Harbor Fort Wilkins is warmer than 7 of the 140 places with their own NOAA record in Michigan, and wetter than 40. Across the 7,247 U.S. stations with normals, its annual mean of 40.8°F is warmer than 7%.
In the Köppen classification computed from these normals, Copper Harbor Fort Wilkins is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Questions about Copper Harbor Fort Wilkins's climate
What is the coldest month at Copper Harbor Fort Wilkins?
January, with a normal high of 23°F and a normal low of 11°F. The warmest is August (73°F by day, 56°F at night).
What is the rainiest month at Copper Harbor Fort Wilkins?
October, with 3.72 in of precipitation in a normal year; the driest is March with 1.70 in.
What plant hardiness zone is Copper Harbor Fort Wilkins in?
The USDA's 2023 map puts Copper Harbor Fort Wilkins in zone 6a in ZIP code 49918, the nearest ZIP area.
How late can frost come at Copper Harbor Fort Wilkins?
In half of years the last 32°F night comes after May 20; in one year in ten it comes after June 3. Waiting until June 3 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Michigan climateThe statewide normals and every place in the state
- Copper Harbor, MI1 miles from this station, 42.5°F a year
- Hancock, MI35 miles from this station, 40.7°F a year
- Jacobsville, MI42 miles from this station, 39.9°F a year
- Big Bay, MI44 miles from this station, 41.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made