Grattan, MI climate
Grattan has chilly, snowy winters and pleasant summers. A typical July afternoon reaches 82°, a January night drops to 15°, and about 66 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Grattan feels like
Winter
Spring
Summer
Fall
Grattan 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 30° | 15° | 2.5" | 21.3" | 15 | 13° – 32° |
| February | 33° | 16° | 2.0" | 16.1" | 11 | 11° – 33° |
| March | 44° | 24° | 2.4" | 7.2" | 10 | 25° – 49° |
| April | 57° | 34° | 3.7" | 1.3" | 13 | 38° – 51° |
| May | 69° | 45° | 3.9" | 0 | 12 | 49° – 63° |
| June | 78° | 55° | 3.7" | 0 | 11 | 63° – 72° |
| July | 82° | 59° | 3.3" | 0 | 9 | 65° – 76° |
| August | 80° | 57° | 3.6" | 0 | 10 | 63° – 74° |
| September | 73° | 50° | 3.2" | 0 | 10 | 55° – 65° |
| October | 60° | 39° | 3.8" | 0.2" | 11 | 46° – 56° |
| November | 46° | 30° | 3.0" | 4.0" | 12 | 31° – 46° |
| December | 35° | 22° | 2.4" | 15.8" | 13 | 18° – 38° |
| Year | 57° | 37° | 37.4" | 65.9" | 135 |
“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 Grattan
Grattan gets 37 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 135 days a year.
About 133 frost-free days a year
In half of years the last 32° night comes by May 18 and the first one by September 28. That leaves about 133 frost-free days for gardens, shorter than 93% of U.S. towns.
Heating and cooling a home in Grattan
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Grattan, 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.
Grattan and its neighbors
Grattan borders 4 towns with climate data. January nights across them vary by 0.8°. Oakfield has both the coldest January nights (15°) and the hottest July afternoons (83°). Grattan’s January low is 15° and its July high 82°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Grattan 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 Grattan averaged 1.4° warmer than the 1900s. The biggest change is in December (+2.9°). The shift is larger than in 67% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Grattan’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 49°. June is the most reliable, staying within 9°.
Common questions about Grattan’s climate
What is the coldest month in Grattan?
January, with a typical high of 30° and a low of 15°.
What is the hottest month in Grattan?
July, with a typical high of 82° and a low of 59°. About 14 days a year reach 90°.
How much snow does Grattan get?
About 66 inches in a normal winter, most of it in January.
When is the first frost in Grattan?
In half of years the first 32° night comes by September 28, and the last spring frost by May 18.
What is the rainiest month in Grattan?
May, with 3.9 inches of rain and melted snow. The year totals 37 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Grattan itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Lowell, MI (10 mi, snow) and Greenville 2 Nne, MI (11 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.