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Climate in Wilmington, Delaware: Monthly Weather Averages

By the AverageClimate Editorial Team · Last updated: October 2026

Wilmington sits at 79 feet above sea level, and its climate, as recorded at the Wilmington New Castle County Airport, DE station, runs to a yearly mean of 55.5°F. The warmest month is July, averaging 77.6°F with typical highs of 86.8°F; the coldest is January, averaging 33.5°F with lows around 25.6°F. Across a normal year the city receives 45.3 in of precipitation and 20.2 in of snow. The full month-by-month picture below comes from the official 1991–2020 U.S. Climate Normals — the 30-year averages the National Weather Service itself uses — so it describes the Wilmington climate you should actually plan around, whether you are timing a visit, weighing a move, or just settling an argument about which month is best.

Wilmington climate month by month

The table below is the complete 1991–2020 normals profile for Wilmington: average high, average low and mean temperature, rainfall, and snowfall for every month. Read down the Mean column to feel the year's rhythm — Wilmington's temperature range runs from 33.5°F in January to 77.6°F in July.

How to read the colors:below freezingcoldcoolmildwarmhot. Bands are colored by each cell's own temperature, so a whole year reads at a glance.

Wilmington through the seasons

Winter in Wilmington averages highs of 41.4–46.0°F and lows of 25.6–30.3°F, a seasonal mean of 35.7°F. The three months together bring 9.9 in of precipitation — about 22% of the city's yearly total — with December the wettest of the three at 3.85 in. Snowfall averages 16.8 in over the season, most of it in February (7.8 in). It is a genuinely cold season — heavy coats, freezing nights, and the year's most changeable weather — without being locked below freezing around the clock.

Spring in Wilmington averages highs of 52.5–73.5°F and lows of 33.9–53.4°F, a seasonal mean of 53.5°F. The three months together bring 11.2 in of precipitation — about 25% of the city's yearly total — with March the wettest of the three at 4.16 in. Snowfall averages 3.2 in over the season, most of it in March (3.1 in). The season is a transition: the average temperature climbs 20.3°F from March to May, and by late spring Wilmington is firmly into mild territory, with May rainfall of 3.57 in to plan around.

Summer in Wilmington averages highs of 82.2–86.8°F and lows of 63.0–68.3°F, a seasonal mean of 75.3°F. The three months together bring 13.1 in of precipitation — about 29% of the city's yearly total — with June the wettest of the three at 4.67 in. It is a warm, usable summer: afternoons are hot enough for swimming and lake or coast time, while evenings usually cool off comfortably.

Fall in Wilmington averages highs of 55.9–78.5°F and lows of 37.4–59.3°F, a seasonal mean of 57.6°F. The three months together bring 11.1 in of precipitation — about 25% of the city's yearly total — with September the wettest of the three at 4.38 in. Snowfall averages 0.2 in over the season, most of it in November (0.2 in). Temperatures ease off through the season — the monthly mean drops 22.3°F from September to November — and fall is when Wilmington's weather turns crisp and dry, while nights stay mostly frost-free into December.

Best and worst months to visit Wilmington

Ranking every month by its normals — mild mean temperatures score best, heavy rain and snow count against — the most comfortable months to visit Wilmington are:

JuneAugustSeptember

June leads the list: average highs of 82.2°F, lows of 63.0°F, and 4.67 in of rain, with snow a non-factor at 0.0 in. The other picks, August and September, offer the same balance in Wilmington's mild stretch of the year. At the other end, January is usually the month to avoid — deep-winter cold, with a mean temperature of 33.5°F and 3.23 in of precipitation plus 6.1 in of snow.

How Wilmington compares

Across the 114 cities in our dataset, the typical city averages 57.8°F for the year and 35.7 in of precipitation. Wilmington runs 2.2°F cooler than that typical city and wetter by 9.7 in a year, ranking #63 of 114 for annual warmth and #33 of 114 for precipitation (wettest first). Its year-round temperature swing — warmest month minus coldest — is 44.1°F, which puts it in the moderate, clearly seasonal camp.

Planning notes for Wilmington

For anyone relocating: average overnight lows drop below freezing in 3 months (January, February, December), so heating, winter tires, and pipe protection are real seasonal concerns; highs reach the 80s on average in 3 months, but 90°F average highs never arrive; 6 months of the year average between 55°F and 80°F, the band most people find comfortable without heating or cooling. Those four facts, all straight from the normals table above, shape everything from a Wilmington wardrobe to its utility bills.

Wilmington climate FAQ

Source: 1991–2020 U.S. Climate Normals, NOAA National Centers for Environmental Information (NCEI) — ncei.noaa.gov. Station: Wilmington New Castle County Airport, DE (USW00013781), elevation 79 ft. Figures checked October 2026.