Midwinter lows in Port Barrington sink below those of 85% of U.S. towns
In July the day’s top temperature is typically 84°. Expect the heaviest rain or snow in June and the lightest in February. It is a dry place: less rain and snow fall here than on 69% of U.S. towns. For walks and days out, the stretch from May to September brings highs of 70–84°.
A year in Port Barrington at a glance
Each month’s typical high and low, and what it brings.
What stands out about Port Barrington’s climate
Compared with towns across the U.S., with Port Barrington’s place in Illinois beside it.
What a year in Port Barrington feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 162 frost-free days a year
In half of years the last 32° night comes by May 1 and the first by October 11. Frost and day counts come from NOAA’s station at Mc Henry -wg Stratton L&d, IL, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Port Barrington’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −12°. 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 35 inches of snow a winter
Snow, measured at Mc Henry -wg Stratton L&d, IL, falls mostly in January. Precipitation (rain plus melted snow) adds up to 38 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 119 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Port Barrington
90% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Mc Henry -wg Stratton L&d, IL.
Living with Port Barrington’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
162 frost-free days in zone 5b. The last frost comes by May 1 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 11.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 1.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Port Barrington from natural hazards, river flooding is the largest share (65%); heat waves, cold waves, winter storms and ice storms together are 17%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Port Barrington and its neighbors
Every town next door is within a degree of Port Barrington in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Port Barrington’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Port Barrington, IL | 15° | 84° | 38" | 35" |
| Sayre, PA | 17° | 84° | 37" | 35" |
| Kendallville, IN | 17° | 83° | 38" | 36" |
| Marshall, MI | 17° | 83° | 37" | 40" |
| Grinnell, IA | 12° | 84° | 38" | 31" |
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 Barrington averaged 1.2° warmer than the 1900s. The biggest change is in December (+2.6°).
A smaller shift than in 62% 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 Barrington compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Port Barrington’s place among Illinois’.
Port Barrington weather by month
Highs, lows and precipitation from NOAA’s grid at Port Barrington’s center; snow, wet days and snow on the ground from Mc Henry -wg Stratton L&d, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 15° | 1.8" | 11.0" | 10 | 20 | 12° – 34° |
| February | 34° | 18° | 1.8" | 8.9" | 8 | 16 | 14° – 38° |
| March | 46° | 27° | 2.3" | 3.9" | 9 | 6 | 27° – 51° |
| April | 58° | 37° | 3.8" | 1.0" | 11 | 1 | 39° – 54° |
| May | 70° | 47° | 4.5" | 0.0" | 13 | 0 | 53° – 65° |
| June | 79° | 57° | 4.6" | 0.0" | 12 | 0 | 64° – 73° |
| July | 84° | 62° | 3.9" | 0.0" | 10 | 0 | 67° – 79° |
| August | 82° | 61° | 3.9" | 0.0" | 10 | 0 | 65° – 77° |
| September | 75° | 53° | 3.5" | 0.0" | 9 | 0 | 58° – 69° |
| October | 62° | 41° | 3.2" | 0.1" | 10 | 0 | 47° – 58° |
| November | 47° | 31° | 2.5" | 1.4" | 8 | 2 | 31° – 48° |
| December | 35° | 21° | 2.1" | 8.2" | 9 | 11 | 15° – 38° |
| Year | 58° | 39° | 37.6" | 34.5" | 119 | 55 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 27° to 51°. June is the most reliable, staying within 9°.
Where Port Barrington’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 Barrington’s center.
- Snow: Mc Henry -wg Stratton L&d, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Mc Henry -wg Stratton L&d, IL, 5 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 Barrington’s climate
What is the weather like in Port Barrington?
A typical July afternoon reaches 84°, a January night drops to 15°, and about 35 inches of snow falls in a normal winter. Colder January nights than 85% of U.S. towns; cooler July afternoons than 65% of U.S. towns.
How cold does it get in Port Barrington in winter?
January nights average 15°. About 144 nights a year reach 32° or below and 13 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Port Barrington get?
About 35 inches in a normal winter at Mc Henry -wg Stratton L&d, IL, most of it in January, with snow on the ground about 55 days a year.
How hot does it get in Port Barrington?
July, with a typical high of 84° and a low of 62°. About 11 days a year reach 90° (Mc Henry -wg Stratton L&d, IL).
When is the first and last frost in Port Barrington?
In half of years the last spring frost (32°) comes by May 1 and the first fall frost by October 11, about 162 frost-free days, at Mc Henry -wg Stratton L&d, IL.
What growing zone is Port Barrington in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −12°.
What is the best time of year to visit Port Barrington?
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 Barrington getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 62% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Port Barrington.
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.