Awesome suggestions everyone! @Raymondo17 If you haven’t discovered yet, when you adjust any of the zone characteristics you can immediately go to the soil moisture graph and see the simulated watering for the next two weeks. That is usually helpful in fine tuning and viewing how zone changes will impact watering frequency.
Glad to hear your green thumb has been able to keep your indeterminate vines growing during the hottest times. Your growing conditions are acceptable because the nights cool off.
Here in the Phoenix area, that’s tough to do when the night-time temps do not drop below the high 80s, although I do have one plant that refuses to die. It’s looking a bit straggly right now and normally I would have pulled the plant out, but it’s in a pot and not taking up space in the veggie beds.
Tomatoes do not set new fruit when the temps are consistently high, because they are self-fertile and the heat causes their pollen to be no longer viable. When the temps fall, those plants will begin to flower and produce fruit again.
Fortunately there are so many varieties of tomato that it’s easier to find one that suitable for different climates and growing conditions. What variety of tomatoes do you find best for your climate?
The responses posted by @ssindelman, @azdavidr and @Kubisuro are great suggestions. After double-checking settings as @azdavidr outlined, I would check the crop coefficient and bump it up a bit during the hottest part of the summer.
Alternately, you could create a new fixed schedule with durations of your choosing to get your plants through the summer.
With looking at your setting, I’m puzzled why you aren’t watering more often. You’ve already got the crop coefficient at 100%, so you’re telling the system that the plants need lots of water. My first thought is to try upping this even more. I don’t know what the Rachio upper limit is, but I would sure try 110-115 if I could. Your root depth looks like it’s good for the tomatoes, but they probably have the deepest roots, so I would think the other plants would be suffering even more. You could put your allowed depletion to 20 or 25% – that’s what I’ve seen recommended from other sources, and for all my annuals and perennials, I’ve set it at 25%. Another big change might be to set the nozzle inches down. I don’t know what your dripline is putting out — I use mostly 1/2GPH emitters, and I’ve set mine at .2 inches per hour — that would definitely get you more watering time.
You’ve been getting great suggestions from everyone on this thread!!!
After you try some of these changes and if you are still not happy with the results, I agree with @sunny about maybe putting the garden on a fixed schedule.
Wow, I’m blown away by all the good advice here. Thanks everybody!
I appreciate the tip to double check my settings, as now that I look at the new-and-improved Rachio app, clearly some important things have been added. For one thing, I noticed that there are new options. For example, there’s a Zone Type option for “Garden” when before the closest I could get was “Perennials.” Unless I’m mistaken, the Spray Head option for “Drip Line” is new, when before I simply had “Emitter.” I’ve now changed the options to “Garden” and “Drip Line” in the hope that those will yield better results for my vegetable garden.
If I understand this correctly, reducing the Allowed Completion percentage will result in more water being applied. I’ve adjusted this from 30% to 20%. And reducing the Nozzle Inches Per Hour will also add time to the watering sessions. I’ve reduced this from 0.5” to .25”.
I’m going to leave the Crop Coefficient alone for now, as instead of upping the frequency of waterings, I’d prefer to water infrequently yet deeply.
Do the revisions above seem reasonable to add some much-needed moisture to my landscape?
Franz, I must admit that I’m not sure what I’m seeing here in the Soil Moisture section. First off, on the main page for my vegetable garden, it shows 0% for the Soil Moisture. (That sounds bad to me.) Clicking the arrow for more info brings me to what looks like the constellation Cassiopeia – a zig zagged diagram showing a yellow dot at one of the “stars” which touches the Allowed Depletion line. At the bottom is a Fill button and an Empty button. Would you mind giving me the Cliff Notes on how I should interpret this info, and when I would use the Fill or Empty button?
My very favorite tomato variety is Sun Gold, which are golden cherry tomatoes that are incredibly sweet. My kids eat 'em straight off the vine and love ‘em better than candy. We also have good luck with Early Girl and Better Boy. One season I tried several heirloom varieties, like Cherokee Purple, but I found they didn’t seem to care much for Sacramento sizzlin’ summers. At least, I didn’t have much luck with them.
Fun fact, we increased crop coefficient to go up to 150% just for tomatoes.
This explains moisture levels much better than I can. The fun thing is you can click on the right arrow (>) and see our simulated watering for the next two weeks.
No, it’s actually the opposite. When you reduce the Allowed Depletion, you are saying to not let the plant dry out as much and add water sooner. But since the water doesn’t need to go down as far, it’s going to add less water than if it was trying to go down to the wilt level.
I found a really good article on Sweet Peppers and Tomatoes from Utah State University. It’s probably WAY more detail than you will ever want to know, but at the beginning of the article, they recommend an allowed depletion of 25%, but I believe that is based on a tomato root depth of 24". Whatever the root depth, though, most recommendations I have seen for vegetables and annuals and perennials is 25%.
https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1738&context=extension_curall
This change should help quite a bit with the watering time.
I typically don’t recommend from changing the industry standard allowed depletion of 50% 
We have other levers that are easier to understand and change (i.e. crop coefficient).
Interesting article, @Linn. Thanks for sharing. Are you using a soil moisture meter?
Not yet, and I’m getting ready to travel again. But I’m ordering one to have when I get back! Are you using one? I figure the manual ones are cheap enough to give them a try!
I found an inexpensive one that I have used. 
I actually used it to settle a “discussion” about over-watering.
I found it in a garden catalog and think I paid around $15 for it.
Ended the “discussion” and solved the problem.
The one I find most useful is similar to this:
One of the local Master Gardeners makes them. It doesn’t have notches on it, but that’s not really necessary. Absent those, a long, wide-bladed screw driver works just as well.
Great article. Thanks for passing that on, Franz.
Another great article that really helped me to better understand Allowed Depletion. Thanks @Linn .
And thanks to everybody who offered up their sage advice. Much appreciated. I’ll report back in a few weeks.
Seasonal adjust is what the flex schedule is supposed to do.
I don’t believe that applies to Flex Daily, but to fixed schedules. I’m not sure about Flex Monthly.
I think you are in zone 10 according to the temperatures you listed.
I’ll research further. Thank you.
Flex Monthly has a monthly adjustment to account for historical seasonal changes.
Do the “historical seasonal changes” accurately reflect the effect of the increase in global warming rate of the past 15 years?
