Sorry if the table is misleading, guys. The gallons are for the entire month. So, for example, a tree with a 14-foot canopy (maybe in its fifth year in the ground, maybe not) needs about 631 gallons for the entire month of July. If you water every five days, that would amount to around 100 gallons every five days.
In the article I linked to I explained some important factors that affect how much a particular avocado tree will actually need, as well as how much water you may actually have to give it. Some factors include shade, variety, soil type, and water quality.
The table is for trees in full sun and with typical Southern California quality water (read: "salty"). If you have a tree in half-day sun that gets very clean water, you don't need to irrigate it as much.
On this note, for example, I watered a Reed with only stored rainwater one year and it did way better (in terms of foliage appearance and fruit production) than my other trees getting district water.
One last remark: after a tree's been in the ground for a couple years it will be drinking from any water source within reach, sometimes way beyond its canopy edge, and that includes the tree you're irrigating beside it or the neighbor's hedge. So people in urban/suburban settings often don't need to water as much as the table shows. I know of a large Fuerte that "never" gets watered, but it's also got an irrigated lawn growing beneath half its canopy.
Anyway, thanks for the thoughts. And good luck with this heat wave if you live inland like me!