The exceptional weather of April 2021

April 2021 brought exceptional weather to the British Isles. It was characterised by sunny and unusually dry conditions with minimum temperatures much lower than normal. There was drought in many southern areas and late snows were a feature, especially in the north. This paper summarises the climate of April in Ireland, Great Britain and the Crown Dependencies of Guernsey, Jersey and the Isle of Man using data from both official (state-run or state-maintained) stations, supplemented by data from amateur sites, notably those of the Climatological Observers Link. The weather in early spring 2021 affected the growth of many crops and this is also briefly discussed.