Midwinter lows in Danbury sink below those of 94% of U.S. towns
High summer brings afternoon highs near 84°. Seasons differ by 74°, from the coldest nights to the warmest afternoons. By precipitation alone, it ranks drier than 85% of U.S. towns. The heating season runs November to April: each of those months averages under 50°.
A year in Danbury at a glance
Each month’s typical high and low, and what it brings.
What stands out about Danbury’s climate
Compared with towns across the U.S., with Danbury’s place in Iowa beside it.
What a year in Danbury feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 151 frost-free days a year
In half of years the last 32° night comes by May 3 and the first by October 1. Frost and day counts come from NOAA’s station at Mapleton No.2, IA, 6 miles from the town’s center, at about the same height.
The 2023 USDA map puts Danbury’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −16°. 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 31 inches of snow a winter
Snow, measured at Mapleton No.2, IA, falls mostly in February. Precipitation (rain plus melted snow) adds up to 31 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 86 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Danbury
91% 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 Mapleton No.2, IA.
Living with Danbury’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
151 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 1.
Months with highs of 62–84° and lows of 40° or more: May, June, August and September.
Parks & trails →Of the yearly building losses FEMA expects in Danbury from natural hazards, river flooding is the largest share (55%); heat waves, cold waves, winter storms and ice storms together are 8%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Danbury and similar climates
TownRatings has no climate map of the towns around Danbury yet.
Climates most like Danbury’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 |
|---|---|---|---|---|
| Danbury, IA | 10° | 84° | 31" | 31" |
| Winona, MN | 8° | 83° | 36" | 38" |
| Berlin, WI | 9° | 82° | 33" | 38" |
| Rockford, IL | 13° | 84° | 37" | 37" |
| Mount Pleasant, MI | 15° | 83° | 33" | 39" |
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 Danbury averaged 0.8° warmer than the 1900s. The biggest change is in December (+2.3°).
A smaller shift than in 90% 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 Danbury compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Danbury’s place among Iowa’s.
Danbury weather by month
Highs, lows and precipitation from NOAA’s grid at Danbury’s center; snow, wet days and snow on the ground from Mapleton No.2, IA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 28° | 10° | 0.7" | 6.7" | 5 | 18 | 11° – 34° |
| February | 33° | 15° | 0.9" | 8.6" | 5 | 14 | 14° – 34° |
| March | 47° | 26° | 1.8" | 4.4" | 7 | 6 | 29° – 52° |
| April | 60° | 37° | 3.3" | 1.3" | 9 | 0 | 40° – 55° |
| May | 71° | 48° | 4.4" | 0.1" | 11 | 0 | 55° – 66° |
| June | 81° | 59° | 4.6" | 0.0" | 10 | 0 | 67° – 75° |
| July | 84° | 63° | 3.7" | 0.0" | 8 | 0 | 68° – 79° |
| August | 82° | 60° | 4.0" | 0.0" | 8 | 0 | 66° – 76° |
| September | 76° | 52° | 3.1" | 0.0" | 8 | 0 | 58° – 69° |
| October | 63° | 39° | 2.3" | 0.6" | 7 | 0 | 44° – 56° |
| November | 46° | 26° | 1.4" | 2.3" | 5 | 2 | 26° – 48° |
| December | 33° | 16° | 1.1" | 7.1" | 5 | 10 | 10° – 30° |
| Year | 59° | 38° | 31.3" | 31.1" | 86 | 51 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 29° to 52°. June is the most reliable, staying within 8°.
Where Danbury’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 Danbury’s center.
- Snow: Mapleton No.2, IA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Mapleton No.2, IA, 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 Danbury’s climate
What is the weather like in Danbury?
A typical July afternoon reaches 84°, a January night drops to 10°, and about 31 inches of snow falls in a normal winter. Colder January nights than 94% of U.S. towns; cooler July afternoons than 57% of U.S. towns.
How cold does it get in Danbury in winter?
January nights average 10°. About 156 nights a year reach 32° or below and 18 reach 0° or below. In the coldest January of the last 30 years the month averaged 11°.
How much snow does Danbury get?
About 31 inches in a normal winter at Mapleton No.2, IA, most of it in February, with snow on the ground about 51 days a year.
How hot does it get in Danbury?
July, with a typical high of 84° and a low of 63°. About 20 days a year reach 90° (Mapleton No.2, IA).
When is the first and last frost in Danbury?
In half of years the last spring frost (32°) comes by May 3 and the first fall frost by October 1, about 151 frost-free days, at Mapleton No.2, IA.
What growing zone is Danbury in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −16°.
What is the best time of year to visit Danbury?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Danbury getting warmer?
Yes: 1991–2020 averaged 0.8° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 90% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Danbury.
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.