Few U.S. towns have colder winter nights than Delta
Expect July afternoons of about 79°. Its July afternoons stay fresher than in 95% of U.S. towns. Compared with 1901–2000, the average now sits 1.7° higher. Garden planting can start around May 20; autumn frost returns near October 1.
A year in Delta at a glance
Each month’s typical high and low, and what it brings.
What stands out about Delta’s climate
Compared with towns across the U.S., with Delta’s place in Wisconsin beside it.
What a year in Delta feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 132 frost-free days a year
In half of years the last 32° night comes by May 20 and the first by October 1. Frost and day counts come from NOAA’s station at Drummond, WI, 8 miles from the town’s center, 190 ft higher.
The 2023 USDA map puts Delta’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −26°. 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 74 inches of snow a winter
Snow, measured at Drummond, WI, falls mostly in January. Precipitation (rain plus melted snow) adds up to 32 inches a year; July is the wettest month and February the driest. Rain or snow falls on about 112 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Delta
97% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Drummond, WI.
Living with Delta’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
132 frost-free days in zone 4a. The last frost comes by May 20 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: June, July, August and September. 44 miles of trails are waiting.
Parks & trails →Cold waves are 49% of the yearly building losses FEMA expects in Delta from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Delta and its neighbors
Every town next door is within a degree of Delta in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Delta’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 |
|---|---|---|---|---|
| Delta, WI | 2° | 79° | 32" | 74" |
| Iron Mountain, MI | 5° | 80° | 29" | 61" |
| St. Joseph, MN | 3° | 81° | 30" | 57" |
| Beekmantown, NY | 9° | 80° | 35" | 80" |
| Littleton, NH | 6° | 80° | 40" | 68" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Delta averaged 1.7° warmer than the 1900s. The biggest change is in December (+3.7°).
A bigger shift than in 71% 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 Delta compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Delta’s place among Wisconsin’s.
Delta weather by month
Highs, lows and precipitation from NOAA’s grid at Delta’s center; snow, wet days and snow on the ground from Drummond, WI. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 21° | 2° | 1.0" | 15.5" | 9 | −1° – 25° |
| February | 26° | 5° | 1.0" | 12.1" | 6 | 5° – 31° |
| March | 38° | 16° | 1.6" | 12.5" | 8 | 18° – 41° |
| April | 51° | 28° | 2.7" | 6.5" | 10 | 32° – 46° |
| May | 66° | 39° | 3.6" | 0.1" | 10 | 47° – 58° |
| June | 74° | 49° | 4.0" | 0.0" | 11 | 58° – 65° |
| July | 79° | 55° | 4.3" | 0.0" | 11 | 60° – 72° |
| August | 77° | 53° | 3.8" | 0.0" | 10 | 59° – 69° |
| September | 68° | 45° | 3.4" | 0.0" | 10 | 49° – 61° |
| October | 54° | 34° | 3.3" | 1.2" | 10 | 38° – 48° |
| November | 38° | 22° | 2.0" | 12.9" | 8 | 21° – 40° |
| December | 25° | 10° | 1.5" | 13.4" | 9 | 6° – 28° |
| Year | 51° | 30° | 32.0" | 74.2" | 112 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from -1° to 25°. June is the most reliable, staying within 7°.
Where Delta’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 Delta’s center.
- Snow: Drummond, WI.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Drummond, WI, 8 miles from the town’s center, 190 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 Delta’s climate
What is the weather like in Delta?
A typical July afternoon reaches 79°, a January night drops to 2°, and about 74 inches of snow falls in a normal winter. Colder January nights than all but 85 U.S. towns; cooler July afternoons than 95% of U.S. towns.
How cold does it get in Delta in winter?
January nights average 2°. About 183 nights a year reach 32° or below and 35 reach 0° or below. In the coldest January of the last 30 years the month averaged −1°.
How much snow does Delta get?
About 74 inches in a normal winter at Drummond, WI, most of it in January.
How hot does it get in Delta?
July, with a typical high of 79° and a low of 55°. About 3 days a year reach 90° (Drummond, WI).
When is the first and last frost in Delta?
In half of years the last spring frost (32°) comes by May 20 and the first fall frost by October 1, about 132 frost-free days, at Drummond, WI.
What growing zone is Delta in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −26°.
What is the best time of year to visit Delta?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Delta getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 71% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Delta.
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.