Granville has some of the coldest winter nights among U.S. towns
Peak summer warmth arrives in July, with afternoons near 84°. Its yearly precipitation falls short of 85% of U.S. towns. Warming shows here too: 0.8° more than in 1901–2000, led by January. Picnics, hikes and garden evenings come into their own from May to September, with highs of 71–84°.
A year in Granville at a glance
Each month’s typical high and low, and what it brings.
What stands out about Granville’s climate
Compared with towns across the U.S., with Granville’s place in Iowa beside it.
What a year in Granville feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 145 frost-free days a year
In half of years the last 32° night comes by May 5 and the first by September 28. Frost and day counts come from NOAA’s station at Sheldon, IA, 13 miles from the town’s center, at about the same height.
The 2023 USDA map puts Granville’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −19°. 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 27 inches of snow a winter
Snow, measured at Alton, IA, falls mostly in January. Precipitation (rain plus melted snow) adds up to 30 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 81 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Granville
93% 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 Sheldon, IA.
Living with Granville’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
145 frost-free days in zone 5a. The last frost comes by May 5 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 28.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Granville from natural hazards, river flooding is the largest share (34%); heat waves, cold waves, winter storms and ice storms together are 12%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Granville and similar climates
TownRatings has no climate map of the towns around Granville yet.
Climates most like Granville’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 |
|---|---|---|---|---|
| Granville, IA | 8° | 84° | 30" | 27" |
| Lake City, MN | 6° | 83° | 35" | 34" |
| Berlin, WI | 9° | 82° | 33" | 38" |
| Harvard, IL | 13° | 83° | 38" | 32" |
| Brighton, MI | 16° | 82° | 34" | 33" |
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 Granville averaged 0.7° warmer than the 1900s. The biggest change is in January (+2.1°).
A smaller shift than in 92% 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 Granville compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Granville’s place among Iowa’s.
Granville weather by month
Highs, lows and precipitation from NOAA’s grid at Granville’s center; snow, wet days and snow on the ground from Alton, IA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 26° | 8° | 0.7" | 6.4" | 5 | 6° – 31° |
| February | 31° | 12° | 0.9" | 4.8" | 5 | 11° – 33° |
| March | 44° | 24° | 1.7" | 5.2" | 6 | 26° – 50° |
| April | 59° | 35° | 3.1" | 1.2" | 8 | 37° – 54° |
| May | 71° | 47° | 4.2" | 0.0" | 10 | 53° – 65° |
| June | 81° | 58° | 4.6" | 0.0" | 10 | 65° – 74° |
| July | 84° | 62° | 3.5" | 0.0" | 8 | 66° – 79° |
| August | 81° | 59° | 3.5" | 0.0" | 7 | 65° – 75° |
| September | 75° | 50° | 3.2" | 0.0" | 7 | 56° – 67° |
| October | 61° | 38° | 2.3" | 0.3" | 6 | 42° – 54° |
| November | 45° | 24° | 1.4" | 3.1" | 5 | 24° – 45° |
| December | 31° | 13° | 1.0" | 5.6" | 5 | 8° – 28° |
| Year | 57° | 36° | 30.1" | 26.6" | 81 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 6° to 31°. June is the most reliable, staying within 9°.
Where Granville’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 Granville’s center.
- Snow: Alton, IA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sheldon, IA, 13 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 Granville’s climate
What is the weather like in Granville?
A typical July afternoon reaches 84°, a January night drops to 8°, and about 27 inches of snow falls in a normal winter. Colder January nights than 96% of U.S. towns; cooler July afternoons than 63% of U.S. towns.
How cold does it get in Granville in winter?
January nights average 8°. About 171 nights a year reach 32° or below and 29 reach 0° or below. In the coldest January of the last 30 years the month averaged 6°.
How much snow does Granville get?
About 27 inches in a normal winter at Alton, IA, most of it in January.
How hot does it get in Granville?
July, with a typical high of 84° and a low of 62°. About 12 days a year reach 90° (Sheldon, IA).
When is the first and last frost in Granville?
In half of years the last spring frost (32°) comes by May 5 and the first fall frost by September 28, about 145 frost-free days, at Sheldon, IA.
What growing zone is Granville in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −19°.
What is the best time of year to visit Granville?
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 Granville getting warmer?
Yes: 1991–2020 averaged 0.8° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 92% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Granville.
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.