Excuse me, what is the approximate temperature when I go to Northern Europe in mid-April? What clothes should I wear?

In mid-April, it no longer snows in Northern Europe. Spring has arrived. It gets bright at around six o'clock and the days are getting longer. There are birds chirping, but no flowers have bloomed yet. Of course, for southerners who are accustomed to warm sunshine, it is still winter, and it is a severe winter. The weather is cloudy and sunny, sometimes warm and sometimes cold, sometimes sunny and sometimes rainy. We no longer wear thick snow clothes, but even if the sun comes out, it will still be cold if it is windy or rainy, so wear more thermal underwear/pants and sweaters. You still need a jacket, the wind is strong. During the day, the lowest temperature is around 0-5 degrees and the highest temperature is 10-15 degrees.