Plainfield, New Jersey climate: Normal weather by month, frost dates and records
Plainfield's normal year runs from 24°F January nights to 88°F July afternoons, with 48.7 inches of precipitation and 21 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.7°C, January lows of −5°C, July highs of 31°C, 1,237 mm of precipitation a year.
- NOAA stationPlainfield
- Station IDUSC00287079
- Location40.60°N 74.40°W
- Elevation90 ft (27 m)
- From the center1 miles
- Population56,507
On October 23, the normal high in Plainfield is 63°F and the normal low 43°F, and the chance of measurable rain or snow is 28%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Plainfield.
- Jan 41° 24°
- Feb 44° 26°
- Mar 53° 32°
- Apr 66° 42°
- May 75° 51°
- Jun 84° 60°
- Jul 88° 66°
- Aug 86° 64°
- Sep 79° 58°
- Oct 66° 46°
- Nov 56° 36°
- Dec 46° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Plainfield each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 24°F. The most precipitation falls in July (5.34 in), the least in February (3.14 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 41°F | 24°F | 32.2°F | 3.79 | 5.1 | 10 | <1 | 25 | 9 h 30 min |
| February | 44°F | 26°F | 34.9°F | 3.14 | 8.3 | 8 | <1 | 22 | 10 h 40 min |
| March | 53°F | 32°F | 42.5°F | 4.27 | 5.3 | 10 | <1 | 16 | 11 h 50 min |
| April | 66°F | 42°F | 53.7°F | 3.60 | 0.1 | 11 | <1 | 4 | 13 h 10 min |
| May | 75°F | 51°F | 63.1°F | 4.01 | 0.0 | 11 | 2 | <1 | 14 h 20 min |
| June | 84°F | 60°F | 72.0°F | 4.33 | 0.0 | 11 | 6 | <1 | 15 h |
| July | 88°F | 66°F | 77.1°F | 5.34 | 0.0 | 10 | 11 | <1 | 14 h 50 min |
| August | 86°F | 64°F | 75.0°F | 3.99 | 0.0 | 10 | 8 | <1 | 13 h 50 min |
| September | 79°F | 58°F | 68.4°F | 4.27 | 0.0 | 9 | 1 | <1 | 12 h 30 min |
| October | 66°F | 46°F | 56.0°F | 4.31 | 0.0 | 9 | <1 | 2 | 11 h 10 min |
| November | 56°F | 36°F | 45.8°F | 3.48 | 0.2 | 9 | <1 | 12 | 10 h |
| December | 46°F | 29°F | 37.5°F | 4.19 | 2.4 | 10 | <1 | 22 | 9 h 20 min |
| Year (annual) | 65°F | 44°F | 54.9°F | 48.72 | 21.4 | 117 | 29 | 103 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −5°C | 0.1°C | 96 mm | 13 cm |
| February | 7°C | −4°C | 1.6°C | 80 mm | 21 cm |
| March | 12°C | 0°C | 5.8°C | 108 mm | 13 cm |
| April | 19°C | 5°C | 12.1°C | 91 mm | 0 cm |
| May | 24°C | 11°C | 17.3°C | 102 mm | 0 cm |
| June | 29°C | 16°C | 22.2°C | 110 mm | 0 cm |
| July | 31°C | 19°C | 25.1°C | 136 mm | 0 cm |
| August | 30°C | 18°C | 23.9°C | 101 mm | 0 cm |
| September | 26°C | 14°C | 20.2°C | 108 mm | 0 cm |
| October | 19°C | 8°C | 13.3°C | 109 mm | 0 cm |
| November | 13°C | 2°C | 7.7°C | 88 mm | 1 cm |
| December | 8°C | −1°C | 3.1°C | 106 mm | 6 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00287079; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Plainfield?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, October has the fewest days with rain (9).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00287079.
When is the last frost in Plainfield?
In Plainfield, the last spring frost (32°F) comes after April 11 in half of years and after April 27 in one year in ten; the first autumn frost comes before October 28 in half of years and before October 13 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 111 year in 10 after April 27; 9 in 10 after March 31
- First autumn frost, half of years before
- October 281 year in 10 before October 13; 9 in 10 before November 10
NOAA puts the median frost-free season at 198 days, and the season without a hard freeze (28°F) at 223 days.
A hard freeze (28°F) comes after March 31 in half of springs and before November 7 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Plainfield in zone 7a across its 3 ZIP code areas (7a in 07060, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Plainfield's NOAA station is in zone 7a: the coldest night of a typical year reaches 4°F (17 complete years).
Frost dates for every NOAA station in New Jersey · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00287079; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Plainfield ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Plainfield's 3 ZIP code areas are all in zone 7a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Plainfield?
In a normal year in Plainfield, 29 days a year reach 90°F (1 of them 100°F or more), 103 nights fall to 32°F or colder and 117 days bring measurable precipitation.
- Days at 90°F or more
- 29a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 103a normal year
- Days that stay below freezing
- 13high of 32°F or less
- Days with 0.01 inch of precipitation
- 117a normal year
- Days with 1 inch of snow or more
- 5a normal year
The highest temperature in this station's record (since 1888) is 106°F, on July 10, 1936; the lowest is −17°F, on February 9, 1934.
The wettest calendar year on that record is 1975, with 72.99 in; the snowiest season is 1995–96, with 71.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00287079; records: ACIS (NOAA Regional Climate Centers), station USC00287079. Records use complete months only; a month missing more than three days is left out.
How sunny is Plainfield?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Plainfield, 3.9 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (66%). Among the 459 U.S. places of 50,000 or more, that ranks tied 352nd (with 32 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 68% | 1.9 |
| February | 71% | 2.8 |
| March | 69% | 3.7 |
| April | 71% | 4.8 |
| May | 70% | 5.4 |
| June | 76% | 6.0 |
| July | 80% | 6.0 |
| August | 78% | 5.2 |
| September | 76% | 4.3 |
| October | 71% | 3.0 |
| November | 72% | 2.2 |
| December | 66% | 1.6 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Plainfield need?
A normal year in Plainfield brings 4,817 heating degree days, 10% fewer than the median U.S. place (5,373), and 1,157 cooling degree days, 27% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,713 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,015 | 0 |
| February | 841 | 0 |
| March | 699 | 1 |
| April | 353 | 14 |
| May | 127 | 68 |
| June | 16 | 226 |
| July | 1 | 374 |
| August | 1 | 311 |
| September | 43 | 146 |
| October | 295 | 16 |
| November | 576 | 0 |
| December | 851 | 0 |
| Year (annual) | 4,817 | 1,157 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00287079. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Plainfield's climate compare?
Plainfield is warmer than 23 of the other 32 places with their own NOAA record in New Jersey, and wetter than 17. Across the 7,247 U.S. stations with normals, its annual mean of 54.9°F is warmer than 60%.
In the Köppen classification computed from these normals, Plainfield is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Plainfield share this climate record?
15 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- South Plainfield, NJ25,062 people · 2 mi S
- North Plainfield, NJ23,072 people · 2 mi NW
- Iselin, NJ19,151 people · 5 mi SE
- Colonia, NJ18,294 people · 5 mi E
- Metuchen, NJ15,470 people · 5 mi SE
- Middlesex, NJ14,874 people · 5 mi W
- Fords, NJ13,052 people · 7 mi SE
- Bound Brook, NJ12,643 people · 8 mi W
- Dunellen, NJ8,411 people · 3 mi W
- Fanwood, NJ7,968 people · 3 mi N
- Watchung, NJ6,606 people · 3 mi NW
- South Bound Brook, NJ4,965 people · 7 mi SW
- Millington, NJ3,002 people · 8 mi NW
- Menlo Park Terrace, NJ2,952 people · 5 mi SE
- Stirling, NJ2,868 people · 7 mi NW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Plainfield's climate
What is the coldest month in Plainfield?
January, with a normal high of 41°F and a normal low of 24°F. The warmest is July (88°F by day, 66°F at night).
Does it snow in Plainfield?
Yes: 21 inches in a normal year, falling on 7 days with 0.1 inch or more, the most in February (8.3 inches).
What is the rainiest month in Plainfield?
July, with 5.34 in of precipitation in a normal year; the driest is February with 3.14 in.
What plant hardiness zone is Plainfield in?
The USDA's 2023 map puts Plainfield in zone 7a across its 3 ZIP code areas (7a in 07060, the largest). By the same method at Plainfield's NOAA station, the coldest night of a typical year reaches 4°F (17 years, 1991-2020): zone 7a.
How late can frost come in Plainfield?
In half of years the last 32°F night comes after April 11; in one year in ten it comes after April 27. Waiting until April 27 leaves about a one-in-ten chance of a later frost.
Nearby and next
- New Jersey climateThe statewide normals and every place in the state
- Cranford, NJ6 miles from this station, 54.7°F a year
- New Brunswick, NJ9 miles from this station, 53.7°F a year
- Canoe Brook, NJ10 miles from this station, 53.3°F a year
- Newark, NJ14 miles from this station, 55.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made