When Does Spring Officially Start In 2024 Uk. But when is the shortest day and does the solstice mark the start of our coldest season? The seasons are defined as spring (march, april, may), summer (june, july, august), autumn (september,.

Spring is officially deemed to start the week before this, on march 20 during the spring equinox. The spring equinox falls on sunday, march 20 at 3.06am this year and marks the first day of spring for those living in the northern hemisphere, including the uk, europe, north america and most of asia and north africa.