Why did Jonah need a plant for shade if he'd already built a hut?

Question

The book of Jonah states that after Ninevah was saved, Jonah left the city in irritation, built a hut, waited under its shade, and watched the city in the hopes that it would be razed. God then provided a gourd plant to give him shade. Said plant later dies, to Jonah's irritation, and leaves the sun to beat upon his head.

Why did Jonah need a plant, and why was the the sun beating down on his head, when he'd built a hut?

5. Jonah then left the city for a place to the east of it, where he built himself a hut and waited under it in the shade, to see what would happen to the city.
6. Then the LORD God provided a gourd plant. And when it grew up over Jonah’s head, giving shade that relieved him of any discomfort, Jonah was greatly delighted with the plant.
7. But the next morning at dawn God provided a worm that attacked the plant, so that it withered.
8. And when the sun arose, God provided a scorching east wind; and the sun beat upon Jonah’s head till he became faint. Then he wished for death, saying, “It is better for me to die than to live.” [Jonah 4:5-8] [A]

A. https://bible.usccb.org/bible/jonah/4?11=#40004011

Answer 1

Then the LORD God provided a gourd plant. And when it grew up over Jonah’s head, giving shade that relieved him of any discomfort, Jonah was greatly delighted with the plant.

The gourd plant grew on the makeshift hut that Jonah built. Something like this:

It provided a nice shade and probably breeze for Johah under it. Speaking of personal experience as a kid in Hong Kong a long time ago, in terms of temperature, it made a big difference with or without the living plant. I had experienced both. It had to do with oxygen and carbon dioxide exchange in the leaves.

Answer 2

Jonah left the city, went eastwards and built some kind of 'booth' [KJV, YLT].

He waited in the cool of the evening, shaded by his makeshift 'booth' from the setting sun by branches and leaves which would gradually wither during the night. The booth probably did not have much roof on it, but the side parts were enough to shade Jonah from the slanting rays of the evening sun, low in the sky.

In the morning, the gourd came up and provided sufficient extra shade, especially above the head of Jonah, against the heat of the noon and afternoon of that day. The gourd was providential and welcome.

But the next morning, at dawn, the worm attacked the plant. During the morning the plant withered. Jonah then suffered in the heat of the day as, first, a scorching east wind blew about his makeshift shelter, no doubt blowing hotly through the now withered leaves and disturbing the branches and twigs.

After the wind had battered his shelter, the sun beat down upon Jonah's head until he felt faint from heat-stroke and then, finally, wished that he were dead.

All this, to chasten and instruct Jonah. And, also, through him, to teach us all a lesson.

Answer 3

The shade of a live plant is much cooler than a hut made with materials not alive. The way we could tell if a tree that hadn't leafed out yet on a warm spring day was still alive: a live tree would feel cool while a dead tree would feel warm.