Kirkpatrick, Robert Round Barn · Photo: Kevin Schuchmann · CC BY-SA 3.0Nights turn raw in Coggon each January, colder than in 93% of U.S. towns
Expect July afternoons of about 83°. Summers stay cool: July afternoons here are cooler than in 73% of U.S. towns. Warming shows here too: 1.0° more than in 1901–2000, led by December. Warm coats and heating bills mark the months from November to April, when means dip under 50°.
A year in Coggon at a glance
Each month’s typical high and low, and what it brings.
What stands out about Coggon’s climate
Compared with towns across the U.S., with Coggon’s place in Iowa beside it.
What a year in Coggon feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 156 frost-free days a year
In half of years the last 32° night comes by May 3 and the first by October 7. Frost and day counts come from NOAA’s station at Coggon, IA, 0.2 miles from the town’s center, at about the same height.
The 2023 USDA map puts Coggon’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −18°. 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 Manchester #2, IA, falls mostly in January, February and December. Precipitation (rain plus melted snow) adds up to 38 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 117 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Coggon
92% 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 Coggon, IA.
Living with Coggon’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
156 frost-free days in zone 5a. The last frost comes by May 3 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 7.
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 Coggon from natural hazards, river flooding is the largest share (56%); heat waves, cold waves, winter storms and ice storms together are 6%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Coggon and similar climates
TownRatings has no climate map of the towns around Coggon yet.
Climates most like Coggon’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 |
|---|---|---|---|---|
| Coggon, IA | 10° | 83° | 38" | 35" |
| Elkhorn, WI | 13° | 82° | 37" | 34" |
| Woodstock, IL | 14° | 83° | 38" | 35" |
| Lake City, MN | 6° | 83° | 35" | 34" |
| Colchester, VT | 10° | 81° | 38" | 50" |
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 Coggon averaged 1.0° warmer than the 1900s. The biggest change is in December (+2.5°).
A smaller shift than in 75% 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 Coggon compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Coggon’s place among Iowa’s.
Coggon weather by month
Highs, lows and precipitation from NOAA’s grid at Coggon’s center; snow, wet days and snow on the ground from Manchester #2, IA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 27° | 10° | 1.2" | 9.2" | 9 | 21 | 9° – 31° |
| February | 31° | 14° | 1.4" | 8.7" | 8 | 20 | 9° – 36° |
| March | 45° | 26° | 2.2" | 4.2" | 10 | 8 | 28° – 51° |
| April | 59° | 37° | 3.9" | 1.4" | 11 | 1 | 39° – 54° |
| May | 71° | 48° | 4.6" | 0.0" | 13 | 0 | 53° – 66° |
| June | 80° | 58° | 5.9" | 0.0" | 12 | 0 | 66° – 73° |
| July | 83° | 62° | 4.4" | 0.0" | 10 | 0 | 67° – 80° |
| August | 81° | 60° | 4.2" | 0.0" | 10 | 0 | 65° – 77° |
| September | 74° | 51° | 3.8" | 0.0" | 9 | 0 | 57° – 68° |
| October | 61° | 39° | 3.0" | 0.4" | 9 | 0 | 45° – 56° |
| November | 45° | 27° | 2.2" | 2.3" | 8 | 3 | 29° – 47° |
| December | 32° | 17° | 1.7" | 8.5" | 9 | 13 | 10° – 35° |
| Year | 58° | 37° | 38.2" | 34.7" | 117 | 66 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 9° to 36°. June is the most reliable, staying within 7°.
Where Coggon’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 Coggon’s center.
- Snow: Manchester #2, IA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Coggon, IA, 0.2 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 Coggon’s climate
What is the weather like in Coggon?
A typical July afternoon reaches 83°, a January night drops to 10°, and about 35 inches of snow falls in a normal winter. Colder January nights than 93% of U.S. towns; cooler July afternoons than 73% of U.S. towns.
How cold does it get in Coggon in winter?
January nights average 10°. About 160 nights a year reach 32° or below and 24 reach 0° or below. In the coldest January of the last 30 years the month averaged 9°.
How much snow does Coggon get?
About 35 inches in a normal winter at Manchester #2, IA, most of it in January, February and December, with snow on the ground about 66 days a year.
How hot does it get in Coggon?
July, with a typical high of 83° and a low of 62°. About 11 days a year reach 90° (Coggon, IA).
When is the first and last frost in Coggon?
In half of years the last spring frost (32°) comes by May 3 and the first fall frost by October 7, about 156 frost-free days, at Coggon, IA.
What growing zone is Coggon in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −18°.
What is the best time of year to visit Coggon?
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 Coggon getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 75% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Coggon.
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.