When is the last frost in Wilmington, DE?

The average last spring frost (50% probability of 32°F) in Wilmington is around April 7, based on NOAA/NCEI 1991–2020 normals at the Wilmington Porter Rsch, DE station (3.5 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Wilmington?

The average first fall frost in Wilmington, DE is around November 4, giving roughly a 209-day frost-free growing season.

What planting zone is Wilmington, DE?

Wilmington is in USDA plant hardiness zone 7b (average annual extreme minimum temperature 5 to 10°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Wilmington?

In Wilmington, DE the warmest month is July (avg high 84°F) and the coldest is January (avg low 23.8°F). It averages about 50.3″ of precipitation a year and 12″ of snow.

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Wilmington, DE Planting Calendar & Frost Dates

USDA hardiness zone 7b · ZIP 19801 · elevation 82′ · NOAA & USDA data

Wilmington is in USDA hardiness zone 7b (winters can dip to 5 to 10°F), with a growing season of about 209 days between the average last spring frost (April 7) and first fall frost (November 4). The warmest month is July (avg high 84°F); the coldest is January (avg low 23.8°F). It averages 50.3″ of precipitation a year and 12″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 5 to 10°F

Last spring frost

April 7

avg (50% prob, 32°F)

First fall frost

November 4

avg (50% prob, 32°F)

Growing season

209 days

frost-free window

Warmest month

July

avg high 84°F

Month-by-month typical weather in Wilmington

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Wilmington Porter Rsch, DE (3.5 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	37.9	23.8	30.9	3.7	5.3
February	40.9	25.2	33	3	4
March	49.2	32.3	40.8	4.7	1.8
April	61.1	42.5	51.8	4.1	0
May	70.6	52.4	61.5	3.8	0
June	79.4	61.8	70.6	4.7	0
July	84	67.2	75.6	5.2	0
August	81.9	65.7	73.8	4.4	0
September	75	58.6	66.8	5.1	0
October	63.3	47	55.2	4.1	0
November	52.5	36.8	44.7	3.3	0.1
December	42.8	29	35.9	4.4	0.8

What to plant when in Wilmington

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: February 24 · Transplant out: April 14
Peppers	warm	Start seeds indoors: February 10 · Transplant out: April 21
Cucumbers	warm	Direct sow: April 14
Zucchini / squash	warm	Direct sow: April 14
Bush beans	warm	Direct sow: April 14
Sweet corn	warm	Direct sow: April 14
Basil	warm	Transplant out: April 14
Peas	cool	Sow (spring): March 3 · Sow (fall): September 9
Spinach	cool	Sow (spring): February 24 · Sow (fall): September 9
Lettuce	cool	Sow (spring): March 10 · Sow (fall): September 9
Kale	cool	Transplant (spring): March 17 · Sow (fall): August 26
Broccoli	cool	Transplant (spring): March 24
Carrots	cool	Sow (spring): March 17 · Sow (fall): August 26
Onions	cool	Transplant (spring): March 10
Potatoes	cool	Plant seed potatoes: March 24
Radishes	cool	Sow (spring): March 10 · Sow (fall): September 23

Dates are computed from Wilmington's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Delaware

Dover, DE

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Wilmington Porter Rsch, DE, 3.5 mi (confidence: high). Monthly weather normals: Wilmington Porter Rsch, DE, 3.5 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.