Climate and monthly weather forecast
Delaware, USA

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.

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 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.

Spring in Delaware is marked by its mild temperatures and significant changeability. Storms during this season can lead to rapid shifts between warm and cold periods. While spring may be rainier than summer, it provides a refreshing transition from the winter cold to the warmth of summer. With the frost penetration in the soil ranging from 5" (127mm) to 10" (254mm) from north to south, spring becomes a time for nature to rejuvenate and bloom.

Summers in Delaware bring warm to hot conditions, with temperatures of 90°F (32.2°C) and above occurring for 15 to 30 days. The coastal regions can experience oppressive heat due to a higher degree of humidity than the interior. Nevertheless, nights are comfortable, and the growing season ranges from 175 to 195 days. July and August, as the wettest months, contribute to the vibrant green scenery, making summer a lively and lush season in the state.

Autumn is characterized by mild to cold temperatures and the beautiful colors of fall foliage. This season serves as a gentle transition from the hot summer days to the cooler winter months. With an average annual humidity between 63% and 68%, the state experiences a comfortable climate during this period. Autumn's mild weather offers an excellent opportunity for outdoor activities and enjoying the state's natural beauty.

Winter in Delaware sits between the extreme cold of the north and the milder temperatures of the south. Freezing temperatures are not uncommon, with a few nights dipping below 0°F (-17.8°C). Snowfall usually occurs between December and March, with a few flurries in November and April. Despite the potential for cold and snow, the Appalachian Mountains act as a barrier to the cold winds, and the state’s elevation helps moderate the winter chill. The average snowfall during this season adds a serene beauty to the Delaware landscape.

January in Delaware is a part of the winter season, and it tends to be one of the colder months of the year. During this month, temperatures often drop below freezing, although the Appalachian Mountains' presence helps reduce the intensity of the wind and cold. Compared to the mild temperatures of December, January can feel noticeably chillier. Weather in January »

February in Delaware continues the winter season, often marked by the coldest temperatures and the highest snowfall of the year. While January experiences cold conditions, February often records even more freezing temperatures, with nights dipping below 0°F (-17.8°C). Weather in February »

March in Delaware signals the transition from winter to spring, leading to a mixed climate that begins to warm yet still retains the cool of winter. The snowfall that characterizes February starts to decrease, but flurries can still occur, especially in the northern parts of the state. Weather in March »

April in Delaware is a true embodiment of spring, with temperatures rising and the last traces of winter receding. Compared to the cold and snowy conditions of March, April brings a noticeable warming trend. The frost penetration in the soil, once ranging from 5" (127mm) to 10" (254mm) in the winter months, begins to diminish. Temperatures in April are generally mild, offering a pleasant contrast to the winter chill. Weather in April »

May in Delaware marks the full arrival of spring and the anticipation of summer. Temperatures continue to rise throughout the month, creating an agreeable climate that is neither too hot nor too cold. Compared to the transitional weather of April, May exhibits more stability and warmth, leaving behind the last remnants of winter's chill. Daytime temperatures are pleasant, and the nights, while cooler, are generally comfortable. Weather in May »

June in Delaware brings the onset of summer, characterized by warm to hot temperatures that signal a significant shift from the mild climate of May. This month is part of the warm season where the coastal regions might experience oppressive heat due to a higher degree of humidity compared to the interior parts of the state. In June, temperatures can rise to 90°F (32.2°C), particularly during hot and humid periods. Weather in June »

July in Delaware is often considered the peak of summer, with temperatures that can become quite hot. The coastal regions may feel the heat more oppressively due to the high degree of humidity, a significant change from the more temperate climate of June. Temperatures of 90°F (32.2°C) and above are not uncommon in July, occurring for 15 to 30 days during this hot summer month. Weather in July »

August continues the trend of hot summer weather in Delaware, similar to July's conditions but often slightly more tempered. Coastal regions may still experience higher humidity, leading to a perception of greater heat compared to the interior. Temperatures in August can hover around 90°F (32.2°C), and days with such high temperatures are common, though typically fewer in number than in July. Weather in August »

September in Delaware marks the beginning of the transition from hot summer to mild autumn. The month usually starts with summer's warmth but gradually leads into cooler and more pleasant conditions. The coastal regions, though still influenced by humidity, start to experience a decrease in temperature compared to the interior. Temperatures in September begin to decline from the highs of 90°F (32.2°C) that were common in July and August. Weather in September »

October in Delaware ushers in the full splendor of autumn, with temperatures that are significantly cooler than the summer months, yet still mild. The coastal regions continue to experience a moderating influence, but the decreasing humidity allows for a more comfortable climate. Temperatures in October further decline from the transitional phase of September. Weather in October »

November in Delaware is a definitive shift into the late autumn season, with temperatures that continue to drop and the landscape transforming into a winter prelude. The coastal regions may retain some moderating effects, but the overall climate becomes noticeably cooler. Temperatures in November decline further from the mildness of October. Weather in November »

December marks the onset of winter in Delaware, with temperatures that are significantly lower than previous months and a shift toward cold and often freezing conditions. The coastal regions lose most of their moderating influence, and the entire state experiences a more uniform winter climate. Temperatures in December frequently dip to freezing levels, especially during the nights. Weather in December »