Photo: PopePompus · CC BY-SA 4.0Midwinter lows in Patterson sink below those of 90% of U.S. towns
On a normal July day the thermometer tops out near 85°. Winter and summer sit 73° apart. It is a dry place: less rain and snow fall here than on 76% of U.S. towns. Keep the boiler serviced for the months from November to March, which average under 50°.
A year in Patterson at a glance
Each month’s typical high and low, and what it brings.
What stands out about Patterson’s climate
Compared with towns across the U.S., with Patterson’s place in Iowa beside it.
What a year in Patterson feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 157 frost-free days a year
In half of years the last 32° night comes by April 30 and the first by October 3. Frost and day counts come from NOAA’s station at Winterset 1s, IA, 8 miles from the town’s center, 220 ft higher.
The 2023 USDA map puts Patterson’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −14°. 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 Indianola 2w, IA, is heaviest from January through February, about 8 inches a month. Precipitation (rain plus melted snow) adds up to 35 inches a year; May is the wettest month and January the driest. Rain or snow falls on about 96 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Patterson
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 Winterset 1s, IA.
Living with Patterson’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
157 frost-free days in zone 5b. The last frost comes by Apr 30 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 3.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October.
Parks & trails →Of the yearly building losses FEMA expects in Patterson from natural hazards, river flooding is the largest share (49%); heat waves, cold waves, winter storms and ice storms together are 11%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Patterson and similar climates
TownRatings has no climate map of the towns around Patterson yet.
Climates most like Patterson’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 |
|---|---|---|---|---|
| Patterson, IA | 13° | 85° | 35" | 31" |
| Colona, IL | 15° | 85° | 37" | 28" |
| Beloit, WI | 13° | 83° | 37" | 37" |
| Bryan, OH | 18° | 84° | 37" | 29" |
| Westland, MI | 18° | 84° | 34" | 31" |
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 Patterson averaged 0.4° warmer than the 1900s. The biggest change is in December (+2.1°).
A smaller shift than in all but 177 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 Patterson compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Patterson’s place among Iowa’s.
Patterson weather by month
Highs, lows and precipitation from NOAA’s grid at Patterson’s center; snow, wet days and snow on the ground from Indianola 2w, IA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 13° | 0.9" | 8.5" | 5 | 18 | 14° – 35° |
| February | 36° | 17° | 1.2" | 8.2" | 7 | 15 | 16° – 38° |
| March | 49° | 28° | 2.0" | 3.7" | 7 | 5 | 31° – 53° |
| April | 62° | 39° | 3.8" | 1.0" | 10 | 0 | 42° – 57° |
| May | 72° | 50° | 5.1" | 0.3" | 12 | 0 | 56° – 69° |
| June | 82° | 61° | 4.9" | 0.0" | 11 | 0 | 68° – 75° |
| July | 85° | 65° | 4.1" | 0.0" | 8 | 0 | 70° – 82° |
| August | 84° | 62° | 4.0" | 0.0" | 9 | 0 | 67° – 78° |
| September | 77° | 53° | 3.6" | 0.0" | 8 | 0 | 59° – 70° |
| October | 64° | 41° | 2.6" | 0.5" | 8 | 0 | 46° – 58° |
| November | 49° | 29° | 1.8" | 1.9" | 6 | 2 | 30° – 50° |
| December | 36° | 18° | 1.4" | 6.7" | 6 | 10 | 11° – 35° |
| Year | 61° | 40° | 35.4" | 30.8" | 96 | 52 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 11° to 35°. June is the most reliable, staying within 7°.
Where Patterson’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 Patterson’s center.
- Snow: Indianola 2w, IA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Winterset 1s, IA, 8 miles from the town’s center, 220 ft higher; 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 Patterson’s climate
What is the weather like in Patterson?
A typical July afternoon reaches 85°, a January night drops to 13°, and about 31 inches of snow falls in a normal winter. Colder January nights than 90% of U.S. towns; hotter July afternoons than 52% of U.S. towns.
How cold does it get in Patterson in winter?
January nights average 13°. About 145 nights a year reach 32° or below and 15 reach 0° or below. In the coldest January of the last 30 years the month averaged 14°.
How much snow does Patterson get?
About 31 inches in a normal winter at Indianola 2w, IA, heaviest from January through February, about 8 inches a month, with snow on the ground about 52 days a year.
How hot does it get in Patterson?
July, with a typical high of 85° and a low of 65°. About 15 days a year reach 90° (Winterset 1s, IA).
When is the first and last frost in Patterson?
In half of years the last spring frost (32°) comes by April 30 and the first fall frost by October 3, about 157 frost-free days, at Winterset 1s, IA.
What growing zone is Patterson in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −14°.
What is the best time of year to visit Patterson?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Patterson getting warmer?
Yes: 1991–2020 averaged 0.4° warmer than 1901–2000 on NOAA’s grid. A smaller shift than all but 177 U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Patterson.
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.