South Plainfield, NJ climate
South Plainfield has chilly winters and warm summers, with plenty of rain. A typical July afternoon reaches 87°, a January night drops to 23°, and about 29 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in South Plainfield feels like
Winter
Spring
Summer
Fall
South Plainfield 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 | 40° | 23° | 3.5" | 8.3" | 11 | 9 | 23° – 39° |
| February | 43° | 25° | 2.9" | 9.3" | 10 | 10 | 22° – 40° |
| March | 51° | 31° | 4.2" | 5.2" | 11 | 5 | 36° – 50° |
| April | 63° | 41° | 3.7" | 0.6" | 12 | 0 | 48° – 57° |
| May | 73° | 50° | 4.1" | 0 | 13 | 0 | 57° – 67° |
| June | 82° | 60° | 4.3" | 0 | 11 | 0 | 67° – 74° |
| July | 87° | 65° | 5.0" | 0 | 11 | 0 | 71° – 80° |
| August | 85° | 64° | 4.5" | 0 | 10 | 0 | 70° – 78° |
| September | 78° | 57° | 4.1" | 0 | 9 | 0 | 65° – 72° |
| October | 66° | 45° | 4.2" | 0.2" | 10 | 0 | 51° – 62° |
| November | 55° | 36° | 3.3" | 0.5" | 9 | 0 | 40° – 50° |
| December | 45° | 28° | 4.3" | 4.9" | 10 | 4 | 30° – 48° |
| Year | 64° | 44° | 48.1" | 29.0" | 125 | 27 |
“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 South Plainfield
South Plainfield gets 48 inches of rain and melted snow a year. July is the wettest month and February the driest. Rain or snow falls on about 125 days a year. Snow covers the ground about 27 days of the year.
About 193 frost-free days a year
In half of years the last 32° night comes by April 15 and the first one by October 26. That leaves about 193 frost-free days for gardens, longer than 67% of U.S. towns.
Heating and cooling a home in South Plainfield
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In South Plainfield, 83% of that work is heating and 17% 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.
South Plainfield and its neighbors
South Plainfield borders 2 towns with climate data. January nights across them vary by 1.2°. Piscataway has both the coldest January nights (23°) and the hottest July afternoons (87°). South Plainfield’s January low is 23° and its July high 87°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How South Plainfield 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 South Plainfield averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.7°). The shift is larger than in 97% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at South Plainfield’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 30° to 48°. June is the most reliable, staying within 7°.
Common questions about South Plainfield’s climate
What is the coldest month in South Plainfield?
January, with a typical high of 40° and a low of 23°.
What is the hottest month in South Plainfield?
July, with a typical high of 87° and a low of 65°. About 24 days a year reach 90°.
How much snow does South Plainfield get?
About 29 inches in a normal winter, most of it in February.
When is the first frost in South Plainfield?
In half of years the first 32° night comes by October 26, and the last spring frost by April 15.
What is the rainiest month in South Plainfield?
July, with 5.0 inches of rain and melted snow. The year totals 48 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for South Plainfield itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at New Brunswick 3 Se, NJ (7 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.