Why is "Vietnam" much hotter than "Sweden"

Vietnam and Sweden are typical coastal countries and countries in the northern hemisphere. Vietnam is located in Indochina Peninsula, north of the equator and south of the Tropic of Cancer, with a typical tropical climate. The land is fertile, the climate is humid, the wilderness is thousands of miles, and the primitive tropical rain forest is densely covered. Affected by the tropical ocean monsoon, Vietnam is hot and rainy all the year round, with a hot climate and abundant precipitation. Sweden is one of the five Nordic countries, located in Scandinavia, with a long coastline, and is a typical coastal country. Because of the high latitude, one-fifth of the country is located in the Arctic Circle, with extreme days in summer and extreme nights in winter. Even in summer, the height angle of the sun is very low, so the solar radiation is very weak, but because of the influence of the North Atlantic warm current, winter is not as cold as we thought. Sweden is warm in winter and cool in summer, with pleasant climate, abundant precipitation, dense forests, numerous lakes and pleasant scenery. Sweden has a temperate maritime climate with less annual accumulated temperature. For the above reasons, Vietnam is much hotter than Sweden.