Produce breathes like people do, and like a person, it breathes harder and loses more water on a hot day than on a cool day. The higher the respiration rate, the faster you lose water. For ex., asparagus and peas are very high, leaf lettuce is in the middle, and potatoes and celery are very low. Cooler temperatures slow down respiration. Some vegetables are chilling sensitive.
Soluble solids make vegetables freeze at lower temps than water.
Successful postharvest handling cannot be taught by following a set of rules because there are so many continually changing variables. You need to experiment within your own system to learn what works best for you, and train yourself to notice parameters such as temperature, humidity, wind, crop temperature, ventilation, and rough handling. List of resources is attached to this handout. Produce is coolest just before daybreak. If you can't harvest in the early morning, do it in the evening, or when it's cloudy.