Photo: Nahteecirp · Public domainWinter nights in Knox are colder than in 77% of U.S. towns
On a normal July day the thermometer tops out near 84°. Summers stay cool: July afternoons here are cooler than in 63% of U.S. towns. Compared with 1901–2000, the average now sits 1.3° higher. The frost-free window for a garden runs roughly April 26 to October 19.
A year in Knox at a glance
Each month’s typical high and low, and what it brings.
What stands out about Knox’s climate
Compared with towns across the U.S., with Knox’s place in Indiana beside it.
What a year in Knox feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 174 frost-free days a year
In half of years the last 32° night comes by April 26 and the first by October 19. Frost and day counts come from NOAA’s station at Knox Wwtp, IN, 1.1 miles from the town’s center, at about the same height.
The 2023 USDA map puts Knox’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −11°. 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 29 inches of snow a winter
Snow, measured at Knox Wwtp, IN, falls mostly in January. Precipitation (rain plus melted snow) adds up to 40 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 127 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Knox
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 Knox Wwtp, IN.
Living with Knox’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
174 frost-free days in zone 5b. The last frost comes by Apr 26 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: May, June, July, August, September and October. 0.4 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Knox from natural hazards, river flooding is the largest share (39%); heat waves, cold waves, winter storms and ice storms together are 28%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Knox and similar climates
TownRatings has no climate map of the towns around Knox yet.
Climates most like Knox’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 |
|---|---|---|---|---|
| Knox, IN | 17° | 84° | 40" | 29" |
| Kinderhook, NY | 16° | 84° | 42" | 31" |
| Warren, OH | 19° | 83° | 41" | 28" |
| Kewanee, IL | 14° | 84° | 39" | 31" |
| Bloomsburg, PA | 19° | 84° | 43" | 29" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Knox averaged 1.3° warmer than the 1900s. The biggest change is in December (+2.6°).
A smaller shift than in 57% 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 Knox compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Knox’s place among Indiana’s.
Knox weather by month
Highs, lows and precipitation from NOAA’s grid at Knox’s center; snow, wet days and snow on the ground from Knox Wwtp, IN. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 17° | 2.6" | 9.7" | 12 | 13 | 14° – 37° |
| February | 36° | 20° | 2.2" | 7.5" | 10 | 10 | 16° – 38° |
| March | 48° | 28° | 2.6" | 3.4" | 10 | 3 | 28° – 53° |
| April | 61° | 37° | 3.7" | 0.2" | 12 | 0 | 41° – 55° |
| May | 72° | 49° | 4.3" | 0.0" | 12 | 0 | 54° – 67° |
| June | 81° | 59° | 4.6" | 0.0" | 11 | 0 | 65° – 73° |
| July | 84° | 62° | 4.2" | 0.0" | 10 | 0 | 68° – 79° |
| August | 82° | 60° | 4.2" | 0.0" | 9 | 0 | 66° – 77° |
| September | 76° | 52° | 3.4" | 0.0" | 9 | 0 | 59° – 69° |
| October | 64° | 42° | 3.5" | 0.0" | 10 | 0 | 49° – 59° |
| November | 49° | 32° | 2.9" | 2.0" | 10 | 1 | 33° – 48° |
| December | 37° | 23° | 2.5" | 5.7" | 12 | 6 | 16° – 40° |
| Year | 60° | 40° | 40.4" | 28.5" | 127 | 32 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 28° to 53°. June is the most reliable, staying within 9°.
Where Knox’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 Knox’s center.
- Snow: Knox Wwtp, IN (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Knox Wwtp, IN, 1.1 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 Knox’s climate
What is the weather like in Knox?
A typical July afternoon reaches 84°, a January night drops to 17°, and about 29 inches of snow falls in a normal winter. Colder January nights than 77% of U.S. towns; cooler July afternoons than 63% of U.S. towns.
How cold does it get in Knox in winter?
January nights average 17°. About 137 nights a year reach 32° or below and 10 reach 0° or below. In the coldest January of the last 30 years the month averaged 14°.
How much snow does Knox get?
About 29 inches in a normal winter at Knox Wwtp, IN, most of it in January, with snow on the ground about 32 days a year.
How hot does it get in Knox?
July, with a typical high of 84° and a low of 62°. About 7 days a year reach 90° (Knox Wwtp, IN).
When is the first and last frost in Knox?
In half of years the last spring frost (32°) comes by April 26 and the first fall frost by October 19, about 174 frost-free days, at Knox Wwtp, IN.
What growing zone is Knox in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −11°.
What is the best time of year to visit Knox?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Knox getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 57% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Knox.
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.