Harper, IA climate
Harper has cold winters and warm summers. A typical July afternoon reaches 85°, a January night drops to 13°, and about 25 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Harper feels like
Winter
Spring
Summer
Fall
Harper 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 | 30° | 13° | 1.2" | 7.5" | 8 | 17 | 14° – 34° |
| February | 35° | 17° | 1.6" | 8.1" | 7 | 11 | 14° – 38° |
| March | 49° | 28° | 2.2" | 2.3" | 8 | 3 | 31° – 53° |
| April | 62° | 38° | 3.6" | 0.8" | 10 | 0 | 41° – 57° |
| May | 72° | 50° | 5.1" | 0 | 13 | 0 | 55° – 68° |
| June | 81° | 60° | 5.3" | 0 | 12 | 0 | 68° – 74° |
| July | 85° | 64° | 4.1" | 0 | 9 | 0 | 69° – 81° |
| August | 83° | 61° | 4.2" | 0 | 9 | 0 | 66° – 77° |
| September | 77° | 53° | 3.5" | 0 | 8 | 0 | 59° – 70° |
| October | 64° | 41° | 2.9" | 0.4" | 9 | 0 | 47° – 57° |
| November | 49° | 29° | 2.2" | 1.4" | 8 | 2 | 31° – 49° |
| December | 36° | 19° | 1.6" | 4.7" | 8 | 8 | 12° – 37° |
| Year | 60° | 39° | 37.6" | 25.2" | 109 | 41 |
“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 Harper
Harper 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 109 days a year. Snow covers the ground about 41 days of the year.
About 172 frost-free days a year
In half of years the last 32° night comes by April 24 and the first one by October 15. That leaves about 172 frost-free days for gardens, shorter than 58% of U.S. towns.
Heating and cooling a home in Harper
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Harper, 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.
How Harper 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 Harper averaged 0.8° warmer than the 1900s. The biggest change is in December (+2.3°). The shift is smaller than in 83% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Harper’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 12° to 37°. June is the most reliable, staying within 6°.
Common questions about Harper’s climate
What is the coldest month in Harper?
January, with a typical high of 30° and a low of 13°.
What is the hottest month in Harper?
July, with a typical high of 85° and a low of 64°. About 16 days a year reach 90°.
How much snow does Harper get?
About 25 inches in a normal winter, most of it in February.
When is the first frost in Harper?
In half of years the first 32° night comes by October 15, and the last spring frost by April 24.
What is the rainiest month in Harper?
June, with 5.3 inches of rain and melted snow. The year totals 38 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Harper itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Washington, IA (19 mi, snow) and Sigourney, IA (9 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.