Crystal Lake, IA climate
Crystal Lake has cold, snowy winters and pleasant summers. A typical July afternoon reaches 82°, a January night drops to 7°, and about 44 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Crystal Lake feels like
Winter
Spring
Summer
Fall
Crystal Lake 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 | 24° | 7° | 0.8" | 11.3" | 8 | 24 | 5° – 28° |
| February | 28° | 12° | 1.0" | 10.0" | 8 | 22 | 9° – 31° |
| March | 41° | 24° | 1.9" | 7.0" | 9 | 10 | 25° – 48° |
| April | 57° | 35° | 3.6" | 3.0" | 12 | 1 | 35° – 53° |
| May | 69° | 47° | 4.8" | 0.3" | 14 | 0 | 53° – 65° |
| June | 79° | 58° | 5.1" | 0 | 12 | 0 | 65° – 73° |
| July | 82° | 61° | 4.3" | 0 | 10 | 0 | 65° – 78° |
| August | 79° | 59° | 4.0" | 0 | 9 | 0 | 64° – 74° |
| September | 73° | 51° | 3.5" | 0 | 9 | 0 | 55° – 67° |
| October | 60° | 38° | 2.5" | 0.4" | 9 | 0 | 42° – 54° |
| November | 43° | 25° | 1.6" | 3.0" | 8 | 4 | 24° – 47° |
| December | 29° | 14° | 1.2" | 9.4" | 8 | 16 | 6° – 29° |
| Year | 55° | 36° | 34.3" | 44.4" | 116 | 79 |
“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 Crystal Lake
Crystal Lake gets 34 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 79 days of the year.
About 159 frost-free days a year
In half of years the last 32° night comes by April 30 and the first one by October 7. That leaves about 159 frost-free days for gardens, shorter than 72% of U.S. towns.
Heating and cooling a home in Crystal Lake
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Crystal Lake, 93% of that work is heating and 7% 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 Crystal Lake 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 Crystal Lake averaged 0.8° warmer than the 1900s. The biggest change is in December (+2.5°). The shift is smaller than in 85% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Crystal Lake’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 25° to 48°. June is the most reliable, staying within 8°.
Common questions about Crystal Lake’s climate
What is the coldest month in Crystal Lake?
January, with a typical high of 24° and a low of 7°.
What is the hottest month in Crystal Lake?
July, with a typical high of 82° and a low of 61°. About 9 days a year reach 90°.
How much snow does Crystal Lake get?
About 44 inches in a normal winter, most of it in January.
When is the first frost in Crystal Lake?
In half of years the first 32° night comes by October 7, and the last spring frost by April 30.
What is the rainiest month in Crystal Lake?
June, with 5.1 inches of rain and melted snow. The year totals 34 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Crystal Lake itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Mason City Municipal Airport, IA (24 mi, snow) and Forest City 2 Nne, 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.