Onawa, IA climate
Onawa has cold winters and warm summers. A typical July afternoon reaches 86°, a January night drops to 11°, and about 24 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Onawa feels like
Winter
Spring
Summer
Fall
Onawa 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° | 11° | 0.7" | 5.7" | 4 | 15 | 13° – 34° |
| February | 35° | 16° | 0.8" | 4.9" | 5 | 17 | 15° – 35° |
| March | 49° | 27° | 1.7" | 3.4" | 6 | 3 | 31° – 53° |
| April | 62° | 37° | 3.2" | 1.6" | 9 | 0 | 41° – 56° |
| May | 73° | 49° | 4.5" | 0 | 11 | 0 | 56° – 67° |
| June | 83° | 60° | 4.4" | 0 | 10 | 0 | 68° – 76° |
| July | 86° | 64° | 3.4" | 0 | 8 | 0 | 69° – 81° |
| August | 83° | 61° | 3.9" | 0 | 7 | 0 | 67° – 77° |
| September | 77° | 52° | 3.2" | 0 | 6 | 0 | 58° – 70° |
| October | 64° | 40° | 2.2" | 0.5" | 6 | 0 | 45° – 56° |
| November | 48° | 26° | 1.4" | 0.9" | 4 | 1 | 27° – 48° |
| December | 34° | 16° | 1.1" | 6.9" | 5 | 12 | 12° – 31° |
| Year | 60° | 38° | 30.3" | 23.9" | 80 | 48 |
“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 Onawa
Onawa gets 30 inches of rain and melted snow a year. May is the wettest month and January the driest. Rain or snow falls on about 80 days a year. Snow covers the ground about 48 days of the year.
About 154 frost-free days a year
In half of years the last 32° night comes by May 1 and the first one by October 3. That leaves about 154 frost-free days for gardens, shorter than 77% of U.S. towns.
Heating and cooling a home in Onawa
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Onawa, 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 Onawa 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 Onawa averaged 1.1° warmer than the 1900s. The biggest change is in March (+2.4°). The shift is smaller than in 62% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Onawa’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. March swings the most: between 1991 and 2020 its average temperature ranged from 31° to 53°. June is the most reliable, staying within 8°.
Common questions about Onawa’s climate
What is the coldest month in Onawa?
January, with a typical high of 30° and a low of 11°.
What is the hottest month in Onawa?
July, with a typical high of 86° and a low of 64°. About 27 days a year reach 90°.
How much snow does Onawa get?
About 24 inches in a normal winter, most of it in December.
When is the first frost in Onawa?
In half of years the first 32° night comes by October 3, and the last spring frost by May 1.
What is the rainiest month in Onawa?
May, with 4.5 inches of rain and melted snow. The year totals 30 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Onawa itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Kennebec, IA (6 mi, snow) and Onawa 3nw, IA (3 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.