The best time of the day for drip irrigation is usually in the morning and evening. However, in some cases, the best time to drip irrigate your crops maybe in the afternoon, evening or night. There are circumstances that may necessitate a farmer to irrigate his crops at odd times of the day.
The drip irrigation system can be engaged to irrigate crops any time of the day. However, most farmers prefer irrigating their crops in the morning because of the convenience.

Time of the Day to Drip Irrigate your Crops
Morning
Crops can be irrigated using the trickle irrigation system in the morning between the hours of 6am to 11am. Irrigating in the morning has the advantage of giving the plants a head start to manage the heat stress of the day and transport nutrients around its cells and tissues.
Afternoon
Irrigating in the afternoon may also be the best time for drip irrigation schedule. In tropical areas, afternoons are always very hot. This can cause dehydration for plants, hence, irrigating in the afternoon may help the plants to avoid water and heat stress.
Evening
Evenings can also be a good time to irrigate crops. Irrigating in the evening may improve water retention in plants as there is less heat in the evening. Water evaporation is also lesser in the evening so plants can optimize the usage of water.
Night
Crops can also be irrigated at nights. However, because of the inconvenience of irrigating at nights, farmers and gardeners avoid irrigating their crops in the night. Irrigating crops at night may also increase the risk of fungal diseases of plants. Irrigating at nights may not be a good option for using your drip irrigation system.
From our experience, mornings and evenings are the best time to use your drip irrigation system to irrigate your crops due to lesser chances of evaporation and the ability of the plants to optimally use the water.