Jamestown, WI climate
Jamestown has cold, snowy winters and pleasant summers. A typical July afternoon reaches 83°, a January night drops to 12°, and about 36 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Jamestown feels like
Winter
Spring
Summer
Fall
Jamestown weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 27° | 12° | 1.3" | 11.7" | 8 | 23 | 10° – 32° |
| February | 32° | 15° | 1.5" | 8.6" | 8 | 21 | 10° – 36° |
| March | 45° | 27° | 2.2" | 3.7" | 9 | 8 | 27° – 51° |
| April | 58° | 37° | 3.9" | 0.9" | 12 | 0 | 38° – 54° |
| May | 70° | 49° | 4.3" | 0 | 13 | 0 | 53° – 66° |
| June | 79° | 59° | 5.6" | 0 | 12 | 0 | 66° – 73° |
| July | 83° | 63° | 4.8" | 0 | 9 | 0 | 67° – 79° |
| August | 81° | 61° | 4.0" | 0 | 9 | 0 | 66° – 77° |
| September | 74° | 53° | 3.7" | 0 | 9 | 0 | 57° – 68° |
| October | 61° | 41° | 3.0" | 0.1" | 9 | 0 | 46° – 56° |
| November | 45° | 29° | 2.3" | 1.2" | 8 | 3 | 29° – 47° |
| December | 32° | 18° | 1.7" | 9.9" | 9 | 15 | 11° – 35° |
| Year | 57° | 38° | 38.1" | 36.1" | 116 | 71 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Jamestown
Jamestown gets 38 inches of rain and melted snow a year. June is the wettest month and January the driest. Rain or snow falls on about 116 days a year. Snow covers the ground about 71 days of the year.
About 184 frost-free days a year
In half of years the last 32° night comes by April 19 and the first one by October 21. That leaves about 184 frost-free days for gardens, longer than 57% of U.S. towns.
Heating and cooling a home in Jamestown
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Jamestown, 89% of that work is heating and 11% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Jamestown and its neighbors
Jamestown borders 7 towns with climate data. January nights across them vary by 0.5°. Potosi has the coldest January nights (11°) and Dunleith the hottest July afternoons (83°). Jamestown’s January low is 12° and its July high 83°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Jamestown compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Jamestown averaged 0.9° warmer than the 1900s. The biggest change is in December (+2.1°). The shift is smaller than in 80% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Jamestown’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 10° to 36°. June is the most reliable, staying within 7°.
Common questions about Jamestown’s climate
What is the coldest month in Jamestown?
January, with a typical high of 27° and a low of 12°.
What is the hottest month in Jamestown?
July, with a typical high of 83° and a low of 63°. About 18 days a year reach 90°.
How much snow does Jamestown get?
About 36 inches in a normal winter, most of it in January.
When is the first frost in Jamestown?
In half of years the first 32° night comes by October 21, and the last spring frost by April 19.
What is the rainiest month in Jamestown?
June, with 5.6 inches of rain and melted snow. The year totals 38 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Jamestown itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Dubuque L&d 11, IA (3 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.