The climate in Jamaica Township sits close to the middle of U.S. towns
In January the night’s low is typically 18°. Winter nights are cold: in January they are colder than in 68% of U.S. towns. Compared with 1901–2000, the average now sits 1.0° higher. Seedlings are safe outdoors from about April 19, with the first autumn frost due around October 19.
A year in Jamaica Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Jamaica Township’s climate
Compared with towns across the U.S., with Jamaica Township’s place in Illinois beside it.
What a year in Jamaica Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 181 frost-free days a year
In half of years the last 32° night comes by April 19 and the first by October 19. Frost and day counts come from NOAA’s station at Sidell 4n, IL, 1.6 miles from the town’s center, at about the same height.
The 2023 USDA map puts Jamaica Township’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −9°. 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 24 inches of snow a winter
Snow, measured at Sidell 4n, IL, is heaviest from January through February, about 7 inches a month. Precipitation (rain plus melted snow) adds up to 41 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 122 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Jamaica Township
86% 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 Sidell 4n, IL.
Living with Jamaica Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
181 frost-free days in zone 6a. The last frost comes by Apr 19 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 19.
Months with highs of 62–84° and lows of 40° or more: April, May, June, August, September and October. 3.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Jamaica Township from natural hazards, river flooding is the largest share (35%); heat waves, cold waves, winter storms and ice storms together are 19%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Jamaica Township and its neighbors
Every town next door is within a degree of Jamaica Township in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Jamaica Township’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 |
|---|---|---|---|---|
| Jamaica Township, IL | 18° | 85° | 41" | 24" |
| Delaware, OH | 20° | 85° | 41" | 24" |
| Huntingdon, PA | 21° | 85° | 40" | 26" |
| Decatur, IN | 19° | 84° | 40" | 28" |
| Keokuk, IA | 18° | 86° | 40" | 23" |
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 Jamaica Township averaged 1.0° warmer than the 1900s. The biggest change is in December (+2.1°).
A smaller shift than in 77% 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 Jamaica Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Jamaica Township’s place among Illinois’.
Jamaica Township weather by month
Highs, lows and precipitation from NOAA’s grid at Jamaica Township’s center; snow, wet days and snow on the ground from Sidell 4n, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 35° | 18° | 2.4" | 7.1" | 10 | 13 | 19° – 39° |
| February | 40° | 22° | 2.0" | 6.7" | 10 | 9 | 19° – 42° |
| March | 51° | 31° | 2.9" | 2.4" | 11 | 3 | 34° – 55° |
| April | 64° | 41° | 4.2" | 0.4" | 12 | 0 | 45° – 58° |
| May | 74° | 52° | 4.5" | 0.0" | 12 | 0 | 57° – 71° |
| June | 83° | 61° | 4.9" | 0.0" | 11 | 0 | 68° – 75° |
| July | 85° | 64° | 4.2" | 0.0" | 9 | 0 | 69° – 81° |
| August | 84° | 62° | 3.4" | 0.0" | 8 | 0 | 68° – 78° |
| September | 79° | 54° | 3.0" | 0.0" | 8 | 0 | 61° – 71° |
| October | 66° | 43° | 3.4" | 0.0" | 9 | 0 | 50° – 60° |
| November | 51° | 33° | 3.3" | 1.1" | 11 | 1 | 34° – 49° |
| December | 39° | 24° | 2.5" | 6.0" | 11 | 8 | 18° – 41° |
| Year | 63° | 42° | 40.8" | 23.7" | 122 | 33 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 18° to 41°. June is the most reliable, staying within 8°.
Where Jamaica Township’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 Jamaica Township’s center.
- Snow: Sidell 4n, IL (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sidell 4n, IL, 1.6 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 Jamaica Township’s climate
What is the weather like in Jamaica Township?
A typical July afternoon reaches 85°, a January night drops to 18°, and about 24 inches of snow falls in a normal winter. Colder January nights than 68% of U.S. towns; cooler July afternoons than 50% of U.S. towns.
How cold does it get in Jamaica Township in winter?
January nights average 18°. About 126 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 19°.
How much snow does Jamaica Township get?
About 24 inches in a normal winter at Sidell 4n, IL, heaviest from January through February, about 7 inches a month, with snow on the ground about 33 days a year.
How hot does it get in Jamaica Township?
July, with a typical high of 85° and a low of 64°. About 23 days a year reach 90° (Sidell 4n, IL).
When is the first and last frost in Jamaica Township?
In half of years the last spring frost (32°) comes by April 19 and the first fall frost by October 19, about 181 frost-free days, at Sidell 4n, IL.
What growing zone is Jamaica Township in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −9°.
What is the best time of year to visit Jamaica Township?
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 Jamaica Township getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 77% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Jamaica Township.
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.