If you don't irrigate during the day in hot climates some crops will die, and the yields will be terrible for most.
Its a much more complex problem though. Most farms in the US depend on debt and subsidies to get by. That money comes with strings attached, from the yield required to cover expenses to subsidies that require mono-cropped fields that basically sit idle in the off season or when a crop fails.
There are different techniques that could be used, but none of them will match the sheer tonnage of yield from a mono-crop drenched in fertilizer, herbicides, and laid out in a way that allows for massive tractors and combines to be used. All of these methods cause huge damage to the land, but again I'd argue we've left those farmers with little to no choice in the matter given how our food system is designed.
But in the Fresno/Bakersfield area of California, with only 5-10” if rain per year, over pumping is making farming uneconomic. See SGMA https://en.wikipedia.org/wiki/Sustainable_Groundwater_Manage...
That is clearly not true.
Most crops are fine with watering after sunset / before sunrise.
Tomatoes are actually pretty robust, if you grow them properly.
The way I was taught to maximise survival / yield in hot climates is to grow as seedlings for a few weeks, until they're maybe 30cm or so tall. Dig holes ~ 25cm deep, flood / drain / flood / drain - and then take all but the upper few branches off the seedling, and plant, backfill with soil, so about 5m is above-ground.
Because they have adventitious rooting you've effectively just given them a massive reservoir of water retention. This is obviously expensive at scale (though not intrinsically infeasible) but works superbly well in hostile, arid climates.
I expect the next decade or two will force a lot of changes to the way food is grow in already marginal climates.