It isn't something that the average gardener would think about, but your irrigation in some ways may be limiting the growth of your plants if the water is too cold. Biology in the soil tends to be more active when the soil is warm. If you are watering with 50 degree water then you may be cooling the soil and slowing the biology that feeds the soil. It is one reason I use soil heating cables. In the Spring, when my plants are smaller I typically warm my water before watering. As the plants get bigger that becomes more of a challenge. I know growers that have large, black painted water tanks that are used to warm the irrigation water. I don't have that, so I installed a portable hot water heater that I'll still working with to get working properly.
I just checked the temperature of the irrigation water. Right now it is 60 degrees. I would guess it was probably 5-10 degrees warmer a month ago. For early morning watering, that is warmer than my typical outdoor temperatures, but not ideal. I'm hoping to water early in the morning with 75-80 degree water. Not sure I'll be able to get enough volume out of my hot water heater to get it that warm.