No, April is not winter in England. England lies in the Northern Hemisphere, where the meteorological seasons are:
April brings lengthening days, blooming flowers (daffodils, bluebells, cherry blossoms), and average temperatures ranging from 7°C to 14°C (45°F–57°F). While "April showers" are common, snow is rare in lowland areas. The countryside turns green, and daylight lasts until roughly 8:00 PM by month's end.