This dataset contains details of the seasonal abundance of each of the life stages of the mosquito species, Culex pipiens, at a field site located at the Centre for Ecology & Hydrology in Wallingford. Immature life stages (eggs, larvae and pupae) were monitored three times per week from March until October 2015, whilst adult counts were taken four times per week from April until October in the same year. Immature Cx. pipiens were monitored using 450 litre circular water butts, sampled using a standard dipping procedure. Adults were monitored using light traps. The adult data also includes counts for mosquito species Culiseta annulata and Aedes geniculatus.