January in Rome bites harder than in 79% of U.S. towns
Expect July afternoons of about 86°. Its yearly precipitation falls short of 71% of U.S. towns. Warming shows here too: 1.3° more than in 1901–2000, led by December. Homes need heating from November to March, the months averaging under 50°.
A year in Rome at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rome’s climate
Compared with towns across the U.S., with Rome’s place in Illinois beside it.
What a year in Rome feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 178 frost-free days a year
In half of years the last 32° night comes by April 20 and the first by October 17. Frost and day counts come from NOAA’s station at Lacon, IL, 11 miles from the town’s center, at about the same height.
The 2023 USDA map puts Rome’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −10°. 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 20 inches of snow a winter
Snow, measured at Chillicothe, IL, falls mostly in January. Precipitation (rain plus melted snow) adds up to 37 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 97 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Rome
83% of the work is heating. 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 Lacon, IL.
Living with Rome’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
178 frost-free days in zone 6a. The last frost comes by Apr 20 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 17.
Months with highs of 62–84° and lows of 40° or more: April, May, June, August, September and October. 0.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Rome from natural hazards, river flooding is the largest share (65%); heat waves, cold waves, winter storms and ice storms together are 22%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Rome and its neighbors
Every town next door is within a degree of Rome in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Rome’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 |
|---|---|---|---|---|
| Rome, IL | 16° | 86° | 37" | 20" |
| Savannah, MO | 18° | 87° | 37" | 21" |
| Centerville, IA | 15° | 85° | 38" | 22" |
| Napoleon, OH | 19° | 85° | 36" | 25" |
| Peru, IN | 19° | 84° | 40" | 21" |
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 Rome averaged 1.3° warmer than the 1900s. The biggest change is in December (+2.6°).
A smaller shift than in 55% 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 Rome compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Rome’s place among Illinois’.
Rome weather by month
Highs, lows and precipitation from NOAA’s grid at Rome’s center; snow, wet days and snow on the ground from Chillicothe, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 33° | 16° | 1.9" | 7.1" | 8 | 17° – 37° |
| February | 38° | 20° | 1.8" | 3.7" | 6 | 16° – 40° |
| March | 50° | 30° | 2.4" | 2.7" | 8 | 33° – 54° |
| April | 64° | 40° | 3.8" | 0.8" | 10 | 44° – 59° |
| May | 74° | 52° | 4.6" | 0.0" | 10 | 57° – 71° |
| June | 83° | 61° | 4.2" | 0.0" | 10 | 68° – 76° |
| July | 86° | 65° | 3.9" | 0.0" | 8 | 70° – 81° |
| August | 84° | 62° | 3.6" | 0.0" | 8 | 67° – 79° |
| September | 78° | 54° | 3.4" | 0.0" | 7 | 61° – 71° |
| October | 65° | 43° | 3.0" | 0.0" | 8 | 49° – 60° |
| November | 50° | 32° | 2.5" | 0.4" | 8 | 33° – 50° |
| December | 38° | 22° | 2.1" | 5.3" | 8 | 16° – 40° |
| Year | 62° | 41° | 37.2" | 20.0" | 97 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 16° to 40°. June is the most reliable, staying within 8°.
Where Rome’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 Rome’s center.
- Snow: Chillicothe, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Lacon, IL, 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 Rome’s climate
What is the weather like in Rome?
A typical July afternoon reaches 86°, a January night drops to 16°, and about 20 inches of snow falls in a normal winter. Colder January nights than 79% of U.S. towns; hotter July afternoons than 55% of U.S. towns.
How cold does it get in Rome in winter?
January nights average 16°. About 121 nights a year reach 32° or below and 6 reach 0° or below. In the coldest January of the last 30 years the month averaged 17°.
How much snow does Rome get?
About 20 inches in a normal winter at Chillicothe, IL, most of it in January.
How hot does it get in Rome?
July, with a typical high of 86° and a low of 65°. About 29 days a year reach 90° (Lacon, IL).
When is the first and last frost in Rome?
In half of years the last spring frost (32°) comes by April 20 and the first fall frost by October 17, about 178 frost-free days, at Lacon, IL.
What growing zone is Rome in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −10°.
What is the best time of year to visit Rome?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Rome getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 55% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Rome.
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.