The climate of Donghae has four clearly distinguished seasons(spring, summer, fall and winter). The annual average temperature is 12.1 ℃ and the temperature range is highly variable the hottest being 24.4℃ in July and the coldest averaging around 0.4℃ in January. Annual average precipitation amounts to 1,432.8mm. The most precipitation is shown in the summer, when the northern Pacific Ocean appears, while the lowest precipitation appears in winter.

The city is mostly mountainous and has natural resources such as Mureung Valley and beautiful beaches. It has a large deposit of limestone, raw material of cement. As the eastern slope of Taebaek Mountains is so steep, the river does not overflow. However, it runs so fast. As a result, the city is sometimes lack of usable water in dry seasons. With well-developed coastal lines, its long-stretched coastal line including Chuam and Haegeumgang is so picturesque and beaches such as the most beautiful and longest beach in Korea, Mangsang Beach, appeal to urban people.

Donghae is the starting point of Donghae Expressway and the local road No. 37 passes through the city. It's the starting point of local road 38 and 42. It has two major international ports, Donghae Port and Mukho Port and serves as outpost of international trade. It is also a forward trade base connecting China, Russia, Japan, and Southeast Asia. It is located at a strategic point putting them at the center of the increasing trade in 21st century East Asia. A railroad between Pohang and Donghae, planned the TSR (Trans Siberian Railroad), and direct lines with Tsurugashi, Japan and Nahotkashi, Russia are being pursued.

As of Dec., 2005, the number of companies registered in Donghae was 7,839 with 28,190 employees. In 2006 alone, Donghae’s trade volume amounted to US$305 Mil. with US$188 Mil. in export and US$117 Mil., in imports.