Monthly weather forecast and climate
Delaware, USA

Flag of Delaware, USA
Flag of Delaware, USA

The climate of Delaware

Delaware has a humid subtropical climate (Köppen climate classification Cfa) with warm to hot summers and mild to cold winters. Delaware lies on the eastern coast of the United States, in the middle of the North and the South. Delaware Bay and Delaware River separate it from New Jersey. Maryland in the south and west, Pennsylvania in the north, New Jersey in the northeast and east, and the Atlantic Ocean in the east and southeast, border the state. The Atlantic Ocean, the Atlantic High, and the Appalachian Mountains mainly influence the climate of the state.

Delaware, the First State, is at sea level and spans a distance of 96 miles in the north-south direction, with a width of 9 to 25 miles from north to south. The mean elevation of the state is the lowest among all the states in America. Ebright Azimuth is the highest point at an altitude of only 136 meters above sea level. The Appalachian Mountains act as a barrier to the cold winds during the winter. The topography is mostly flat except for the extreme north with hills up to 150 meters high. Many portions of the state are low and marshy, and the elevation rises steadily from below 10 meters at the coast to 25 meters in the interior. Numerous streams and estuaries flow in the Chesapeake Bay and the Delaware Bay. Southern Delaware has milder temperatures compared to the north, and consequently, a longer growing season.

Summers are warm to hot in Delaware. The coastal regions have oppressive heat due to the high degree of humidity than the interior. Nights are comfortable, but summer frequently experiences hot and humid periods. Temperatures of 90°F (32.2°C) and above occur for 15 to 30 days in the hot summer. The growing season ranges from 175 to 195 days in the year.
Winters are between the extreme cold of the north and the mild temperatures of the south. Frost penetration in the soil ranges from 5" (127mm) to 10" (254mm) from north to south. Freezing temperatures occasionally occur with few nights dipping below 0°F (-17.8°C). Spring and fall are generally mild, with a significant degree of changeability. Storms often cause a rapid succession of cold and warm periods.

Delaware averages an annual rainfall of 44" (1118mm) to 47" (1194mm) moving from north to south. July and August are the wettest months, but the rainfall distribution is uniform over the year. The average snowfall ranges from 14" (356mm) in the south to 18" (457mm) in the north. Snowfall usually occurs between December and March with flew flurries in November and April. February often records the highest snowfall of the year. Temperature and precipitation vary depending on latitude and altitude. Delaware has 198 to 202 sunny days in the year, and the average annual humidity is between 63% and 68%.

Millsboro recorded Delaware's highest temperature of 110°F (43.3°C) on July 21, 1930, while Millsboro also recorded the lowest temperature of -17°F (-27.2°C) on January 17, 1893.

The best time to visit Delaware

The best time to visit Delaware is in the summer from June to August when the temperatures are comfortable, and the season is full of festive events. Temperatures are in the warm range of 75°F (23.9°C) to 85°F (29.4°C) with occasional hot days. Delaware coast is popular in the summer as the temperatures are cooler by 10°F (-12.2°C) to 15°F (-9.4°C) compared to the interior. Fall is another good time with lovely colors and mild to cold temperatures. Spring and fall are rainier than the summer with occasionally unexpected weather. However, accommodation rates are costlier in the peak season, and there are crowds everywhere.

The worst time to visit Delaware

The worst time to visit Delaware is from November to February during the cold season.
Cold fronts from the north routinely sweep the state, and temperatures often drop below freezing. Nights are chilly at the peak of the winter even though the mountain ranges reduce the intensity of the wind and cold. Heavy snowfall occurs in February, and there is a chance of a snowstorm lurking on the horizon. The later part of the cold season needs warm clothes and patience to handle transportation delays. Winter is generally an off-season with plenty of deals for budget travelers to take advantage of the low costs of flights and hotels.

Weather hazards

Delaware faces weather hazards in the form of thunderstorms, floods, hurricanes, and snowstorms. Thirty thunderstorms on an average occur in the year with the interior accounting more storms than the Atlantic coast. July has the highest frequency, while May to August accounts for the maximum storms in the year. Cyclones with origin in the Gulf of Mexico bring heavy and widespread rain in Delaware. Flooding occurs from tidal waves as well as tropical cyclones, usually in August and September. Snowfall is heaviest in February and March, but snowstorms occur infrequently. There are records of blizzards that brought 30" (762mm) to 36" (914mm) of snow in a single day.

Weather in January

January is the coldest month of the year in Delaware with frigid nights statewide. The skies are gray, and the sunshine limits to an average of 4 hours a day. The coastal regions are warmer than the interior, but temperatures may drop below 25°F (-3.9°C) in the night. Weather in January »

Weather in February

February is the snowiest month of the year in Delaware and also the period of snowstorms. Icy winds from the north blow towards the state and keep the region cold. The average temperatures are in the cold 26°F (-3.3°C) to 47°F (8.3°C) range. The skies are partly cloudy, but the rainfall rarely crosses 3" (76mm) in the state. Weather in February »

Weather in March

March sees the arrival of the spring season in Delaware that steadily drives the cold away. The snowfall decreases significantly, but there is a chance of icy precipitation when a cold front invades from the north. The ground remains hard with the sun rays yet to regain full strength. Weather in March »

Weather in April

April is a warm month in the spring season of Delaware with partly cloudy skies. The last snow of the season usually disappears by the first week of April, and the landscape turns green. The average temperatures are between a warm 42°F (5.6°C) to 67°F (19.4°C) with an increase in the number of sunny days. Weather in April »

Weather in May

May brings the radiance of the spring to the fore in Delaware with comfortably warm weather. The peak of the spring season coincides with a marked increase in precipitation. The average high temperatures are in the pleasant 73°F (22.8°C) to 77°F (25°C), while the nights are in the mild range of 51°F (10.6°C) to 55°F (12.8°C). Precipitation of 5" (127mm) occurs mostly in the afternoons. Weather in May »

Weather in June

June is the beginning of the majestic summer season in Delaware with long and sunny days. The rainfall is noticeably lesser than the spring, as is the occurrence of storms. The average high temperatures are in the warm 82°F (27.8°C) to 85°F (29.4°C) range, while the average low temperatures are in the comfortable 60°F (15.6°C) to 63°F (17.2°C) zone. Weather in June »

Weather in July

July is usually the hottest month of the year in Delaware, with peak temperatures often exceeding 100°F (37.8°C). The daylight lasts for 15 hours in the majority of the state with intense sunshine. Day high temperatures are the highest in the northern interior and remain moderate near the coast due to the influence of the Atlantic Ocean. Weather in July »

Weather in August

August is hot in Delaware with clear skies and sunny days amid short periods of heavy rain. An increase in humidity levels often accompanies the heat during summer. August is the wettest month with 5" (127mm) to 7" (178mm) of rainfall as a result of many thunderstorms that sweep the state. Weather in August »

Weather in September

September begins the lovely fall season in Delaware with mild conditions amid partly cloudy skies. The rainfall sees an increase with the departure of the hot summer temperatures. Summer thunderstorms exit the state by the early fall season, and the weather is comfortable with many sunny days in the month. The average temperatures register in the 59°F (15°C) to 79°F (26.1°C) range with a significant drop in humidity. Weather in September »

Weather in October

October is the time of colorful foliage in Delaware at the height of the fall season. The mornings and evenings are mild, while the afternoons are warm and delightful. Temperatures drop significantly to register in the 45°F (7.2°C) to 69°F (20.6°C) range across the state. The fall foliage is at its peak during the mid of October and offers unmatched views with an array of colors on display. Weather in October »

Weather in November

November is the last stop of the fall season in Delaware as the weather changes drastically. The temperatures subside rapidly, and cold fronts from the north become frequent. The average temperatures register between a cold 39°F (3.9°C) to a warm 59°F (15°C). Weather in November »

Weather in December

December is the beginning of the cold winter in Delaware with short days amid mild sunshine. The interior and northern parts of the state receive higher snowfall than the rest. The average high temperatures are in the mild 45°F (7.2°C) to 49°F (9.4°C) range, while the average low temperatures lie in the cold 28°F (-2.2°C) to 34°F (1.1°C) zone. Weather in December »


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