Photo: Traveler100 · CC BY-SA 3.0Few U.S. towns have cooler summers than Port Sanilac
Midwinter brings lows of about 18°. Its yearly precipitation falls short of 82% of U.S. towns. The latest 30-year average runs 1.6° warmer than 1901–2000’s, with December up the most. Keep the boiler serviced for the months from November to April, which average under 50°.
A year in Port Sanilac at a glance
Each month’s typical high and low, and what it brings.
What stands out about Port Sanilac’s climate
Compared with towns across the U.S., with Port Sanilac’s place in Michigan beside it.
What a year in Port Sanilac feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 171 frost-free days a year
In half of years the last 32° night comes by May 4 and the first by October 24. Frost and day counts come from NOAA’s station at Lexington Wtp, MI, 11 miles from the town’s center, at about the same height.
The 2023 USDA map puts Port Sanilac’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −5°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 33 inches of rain a year
May is the wettest month and February the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Port Sanilac
94% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Lexington Wtp, MI.
Living with Port Sanilac’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
171 frost-free days in zone 6a. The last frost comes by May 4 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 24.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.1 miles of trails are waiting.
Parks & trails →Cold waves are 48% of the yearly building losses FEMA expects in Port Sanilac from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Port Sanilac and its neighbors
Sanilac Township has the coldest January nights next door (17°, 1° colder). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Port Sanilac averaged 1.6° warmer than the 1900s. The biggest change is in December (+2.8°).
A bigger shift than in 64% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Port Sanilac compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Port Sanilac’s place among Michigan’s.
Port Sanilac weather by month
Highs, lows and precipitation from NOAA’s grid at Port Sanilac’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 30° | 18° | 2.3" | 13° – 33° |
| February | 32° | 19° | 1.9" | 10° – 34° |
| March | 40° | 26° | 2.1" | 23° – 46° |
| April | 52° | 36° | 3.2" | 37° – 49° |
| May | 64° | 46° | 3.4" | 48° – 61° |
| June | 74° | 56° | 3.2" | 60° – 69° |
| July | 79° | 62° | 3.1" | 64° – 75° |
| August | 78° | 61° | 3.2" | 65° – 74° |
| September | 71° | 54° | 3.1" | 58° – 68° |
| October | 59° | 44° | 3.0" | 48° – 58° |
| November | 46° | 34° | 2.5" | 33° – 46° |
| December | 35° | 25° | 2.3" | 19° – 40° |
| Year | 55° | 40° | 33.0" |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 10° to 34°. June is the most reliable, staying within 9°.
Where Port Sanilac’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Port Sanilac’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Lexington Wtp, MI, 11 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Port Sanilac’s climate
What is the weather like in Port Sanilac?
A typical July afternoon reaches 79°, a January night drops to 18°. Colder January nights than 69% of U.S. towns; cooler July afternoons than 95% of U.S. towns.
How cold does it get in Port Sanilac in winter?
January nights average 18°. About 140 nights a year reach 32° or below and 8 reach 0° or below. In the coldest January of the last 30 years the month averaged 13°.
How hot does it get in Port Sanilac?
July, with a typical high of 79° and a low of 62°. About 6 days a year reach 90° (Lexington Wtp, MI).
When is the first and last frost in Port Sanilac?
In half of years the last spring frost (32°) comes by May 4 and the first fall frost by October 24, about 171 frost-free days, at Lexington Wtp, MI.
What growing zone is Port Sanilac in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −5°.
What is the best time of year to visit Port Sanilac?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Port Sanilac getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 64% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Port Sanilac.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.