Wilmington Porter Research, Delaware climate: Climate normals at a NOAA weather station
Wilmington Porter Research's normal year runs from 24°F January nights to 84°F July afternoons, with 50.3 inches of precipitation and 12 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.9°C, January lows of −5°C, July highs of 29°C, 1,278 mm of precipitation a year.
- NOAA stationWilmington Porter Research
- Station IDUSC00079605
- Location39.77°N 75.54°W
- Elevation270 ft (82 m)
On October 23, the normal high in Wilmington Porter Research is 61°F and the normal low 44°F, and the chance of measurable rain or snow is 27%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Wilmington Porter Research.
- Jan 38° 24°
- Feb 41° 25°
- Mar 49° 32°
- Apr 61° 43°
- May 71° 52°
- Jun 79° 62°
- Jul 84° 67°
- Aug 82° 66°
- Sep 75° 59°
- Oct 63° 47°
- Nov 53° 37°
- Dec 43° 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 at Wilmington Porter Research each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 24°F. The most precipitation falls in July (5.17 in), the least in February (3.03 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 38°F | 24°F | 30.9°F | 3.67 | 5.3 | 10 | <1 | 24 | 9 h 40 min |
| February | 41°F | 25°F | 33.0°F | 3.03 | 4.0 | 9 | <1 | 21 | 10 h 40 min |
| March | 49°F | 32°F | 40.8°F | 4.65 | 1.8 | 11 | <1 | 13 | 11 h 50 min |
| April | 61°F | 43°F | 51.8°F | 4.06 | 0.0 | 10 | <1 | 2 | 13 h 10 min |
| May | 71°F | 52°F | 61.5°F | 3.76 | 0.0 | 11 | 1 | <1 | 14 h 20 min |
| June | 79°F | 62°F | 70.6°F | 4.71 | 0.0 | 10 | 3 | <1 | 15 h |
| July | 84°F | 67°F | 75.6°F | 5.17 | 0.0 | 9 | 8 | <1 | 14 h 40 min |
| August | 82°F | 66°F | 73.8°F | 4.39 | 0.0 | 9 | 4 | <1 | 13 h 50 min |
| September | 75°F | 59°F | 66.8°F | 5.13 | 0.0 | 9 | 1 | <1 | 12 h 30 min |
| October | 63°F | 47°F | 55.2°F | 4.12 | 0.0 | 8 | <1 | <1 | 11 h 10 min |
| November | 53°F | 37°F | 44.7°F | 3.25 | 0.1 | 8 | <1 | 8 | 10 h |
| December | 43°F | 29°F | 35.9°F | 4.37 | 0.8 | 10 | <1 | 19 | 9 h 20 min |
| Year (annual) | 62°F | 45°F | 53.4°F | 50.31 | 12.0 | 113 | 17 | 87 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −5°C | −0.6°C | 93 mm | 13 cm |
| February | 5°C | −4°C | 0.6°C | 77 mm | 10 cm |
| March | 10°C | 0°C | 4.9°C | 118 mm | 5 cm |
| April | 16°C | 6°C | 11.0°C | 103 mm | 0 cm |
| May | 21°C | 11°C | 16.4°C | 96 mm | 0 cm |
| June | 26°C | 17°C | 21.4°C | 120 mm | 0 cm |
| July | 29°C | 20°C | 24.2°C | 131 mm | 0 cm |
| August | 28°C | 19°C | 23.2°C | 112 mm | 0 cm |
| September | 24°C | 15°C | 19.3°C | 130 mm | 0 cm |
| October | 17°C | 8°C | 12.9°C | 105 mm | 0 cm |
| November | 11°C | 3°C | 7.1°C | 83 mm | 0 cm |
| December | 6°C | −2°C | 2.2°C | 111 mm | 2 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00079605; 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.
Which months are mildest at Wilmington Porter Research?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August 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 USC00079605.
When is the last frost at Wilmington Porter Research?
In Wilmington Porter Research, the last spring frost (32°F) comes after April 7 in half of years and after April 24 in one year in ten; the first autumn frost comes before November 4 in half of years and before October 21 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 71 year in 10 after April 24; 9 in 10 after March 26
- First autumn frost, half of years before
- November 41 year in 10 before October 21; 9 in 10 before November 19
NOAA puts the median frost-free season at 209 days, and the season without a hard freeze (28°F) at 232 days.
A hard freeze (28°F) comes after March 29 in half of springs and before November 15 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Wilmington Porter Research in zone 7b in ZIP code 19802, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 7b: the coldest night of a typical year reaches 8°F (26 complete years).
Frost dates for every NOAA station in Delaware · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00079605; 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.
How hot and how cold does it get at Wilmington Porter Research?
In a normal year in Wilmington Porter Research, 17 days a year reach 90°F, 87 nights fall to 32°F or colder and 113 days bring measurable precipitation.
- Days at 90°F or more
- 17a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 87a normal year
- Days that stay below freezing
- 17high of 32°F or less
- Days with 0.01 inch of precipitation
- 113a normal year
- Days with 1 inch of snow or more
- 4a normal year
The highest temperature in this station's record (since 1932) is 103°F, on July 10, 1936; the lowest is −15°F, on February 9, 1934.
The wettest calendar year on that record is 1996, with 68.89 in; the snowiest season is 1995–96, with 48.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00079605; records: ACIS (NOAA Regional Climate Centers), station USC00079605. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Wilmington Porter Research?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds at Wilmington Porter Research, 4.1 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 68% | 2.0 |
| February | 71% | 2.9 |
| March | 69% | 3.8 |
| April | 73% | 5.0 |
| May | 72% | 5.6 |
| June | 78% | 6.2 |
| July | 82% | 6.2 |
| August | 80% | 5.4 |
| September | 77% | 4.4 |
| October | 73% | 3.2 |
| November | 74% | 2.3 |
| December | 68% | 1.8 |
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 many heating and cooling degree days does Wilmington Porter Research record?
A normal year at Wilmington Porter Research brings 5,181 heating degree days, 4% fewer than the median U.S. place (5,373), and 977 cooling degree days, 8% more than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,419 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,058 | 0 |
| February | 895 | 0 |
| March | 752 | 0 |
| April | 404 | 8 |
| May | 159 | 50 |
| June | 23 | 190 |
| July | 0 | 329 |
| August | 2 | 275 |
| September | 58 | 112 |
| October | 319 | 13 |
| November | 611 | 0 |
| December | 902 | 0 |
| Year (annual) | 5,181 | 977 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00079605. 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.
Have recent years at Wilmington Porter Research been warmer than normal?
2024 averaged 56.3°F, 2.9°F above the 1991-2020 normal of 53.4°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 56.1°F | +2.7°F | – | – |
| 2022 | 54.8°F | +1.4°F | – | – |
| 2023 | 56.3°F | +2.9°F | – | – |
| 2024 | 56.3°F | +2.9°F | – | – |
Over 97 complete years from 1914 to 2024, the station's annual mean temperature rose at a fitted 2.6°F per century (+0.14°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00079605; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Wilmington Porter Research's climate compare?
Wilmington Porter Research is warmer than 0 of the 6 places with their own NOAA record in Delaware, and wetter than 6. Across the 7,247 U.S. stations with normals, its annual mean of 53.4°F is warmer than 55%.
In the Köppen classification computed from these normals, Wilmington Porter Research is Dfa: continental, 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 Wilmington Porter Research share this climate record?
28 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.
- Chester, PA34,052 people · 10 mi NE
- Broomall, PA10,684 people · 17 mi NE
- Woodlyn, PA10,276 people · 13 mi NE
- Village Green-Green Ridge, PA8,725 people · 9 mi NE
- Brookhaven, PA8,407 people · 10 mi NE
- Folsom, PA8,298 people · 14 mi NE
- Carneys Point, NJ7,945 people · 6 mi SE
- Ridley Park, PA7,310 people · 14 mi NE
- Kennett Square, PA6,713 people · 10 mi NW
- Swarthmore, PA6,596 people · 14 mi NE
- Media, PA5,938 people · 13 mi NE
- Boothwyn, PA5,129 people · 7 mi NE
- Penns Grove, NJ4,921 people · 5 mi SE
- Linwood, PA3,623 people · 7 mi NE
- Chester Heights, PA3,087 people · 9 mi NE
- Upland, PA3,076 people · 10 mi NE
- Lima, PA2,834 people · 11 mi NE
- Morton, PA2,788 people · 15 mi NE
- Eddystone, PA2,465 people · 12 mi NE
- Parkside, PA2,335 people · 11 mi NE
- Trainer, PA1,984 people · 8 mi NE
- Chadds Ford, PA1,403 people · 8 mi NW
- Dilworthtown, PA1,098 people · 9 mi N
- Rose Valley, PA1,020 people · 12 mi NE
- Rutledge, PA788 people · 14 mi NE
- Unionville, PA764 people · 13 mi NW
- Cheyney University, PA186 people · 11 mi N
- Hamorton, PA161 people · 9 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 Wilmington Porter Research's climate
What is the coldest month at Wilmington Porter Research?
January, with a normal high of 38°F and a normal low of 24°F. The warmest is July (84°F by day, 67°F at night).
Does it snow at Wilmington Porter Research?
Yes: 12 inches in a normal year, falling on 6 days with 0.1 inch or more, the most in January (5.3 inches).
What is the rainiest month at Wilmington Porter Research?
July, with 5.17 in of precipitation in a normal year; the driest is February with 3.03 in.
What plant hardiness zone is Wilmington Porter Research in?
The USDA's 2023 map puts Wilmington Porter Research in zone 7b in ZIP code 19802, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 8°F (26 years, 1991-2020): zone 7b.
How late can frost come at Wilmington Porter Research?
In half of years the last 32°F night comes after April 7; in one year in ten it comes after April 24. Waiting until April 24 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Delaware climateThe statewide normals and every place in the state
- Marcus Hook, PA7 miles from this station, 57.1°F a year
- Wilmington, DE7 miles from this station, 55.5°F a year
- Newark, DE13 miles from this station, 55.7°F a year
- Avondale, PA14 miles from this station, 52.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made