Why do crops require more water in summer

Crops require more water during the summer season because this is their active growing season and because they are losing more water due to the increased temperatures and prolonged daylight.
Most students learn a simple, three part water cycle. It includes precipitation, condensation, and evaporation. Evaporation occurs when liquid water turns into a vapor. Summer means longer days with higher temperatures, and this means more evaporation. A type of evaporation happens to plants. It's called "transpiration." It is the process in which liquid water is moved up a plant from the roots to tiny pores on the leaves, and then the water vaporizes and is released into the atmosphere. Just like summer increases evaporation rates, summer increases transpiration rates as well. Because the plant is losing more water, it needs to obtain more water.
Summer is a plant's growing season. Plants are living organisms, and a basic characteristic of living organisms is the ability to grow and develop. In order to do that, though, an organism must obtain and use energy. Plants obtain and use energy through photosynthesis and cellular respiration. A key ingredient to photosynthesis is water. Plants are doing more photosynthesis during the summer season; therefore, they are using more water.
https://www.usgs.gov/special-topic/water-science-school/science/evapotranspiration-and-water-cycle