I'm not in the Central Valley, but I've talked to a couple people who farm out there and sell at farmer's markets up here in the Bay Area. Generally, I see a lot of Cherokee Purple, Striped German, Brandywine, Black Prince, and Black Krim. I know I've seen some yellows and oranges, but I never pay much attention to them, and I never asked what they were because I wasn't about to buy them.

I'm not in your area either, and my experience is limited. To prevent "thirsty" syndrom I plant the seedings deep and water them evenly, every 1 or 2 days.

This is my "form answer" for hot weather varieties, which is what you're really asking. And if your varieties "look perpetually thirsty", ie drooping, in Stockton it is probably because you have the roots compromised by nematodes. This list is also good for that:

Large varieties for hot weather (above 100 degrees):
Mexico, Giant Belgium, Stump of the World, Marianna's Peace, Big Beef, Brandy Boy, Boondocks

Medium varieties: Stupice, Jetsetter, Arkansas Traveler, Burgundy Traveler, Manalucie, Moskvich, Orange Russian 117 (altough these can grow to beefsteak size), Peron, Jubilee, Heidi

and

just about all cherry/grape tomatoes.

And FYI I have found that it does help with fruit set if you shade them in the hottest part of the day, and hose them down with cool water when the humidity is low.

Carla in Sac

Carla - It's been a long time since I visited here but I did this evening and read your post. I'd like to thank you for the information you provided the OP as I live in the desert of Nevada (outside of LV) and have been looking for tomatoes that can tolerate heat. I'll be giving them a try.

Greg
Nevada

I live in the high desert of So. CA. where the daytime highs are normally between 98 and 105 f. in the summer. All my tomatoes were about 12" tall and set in the ground (or into permanent containers) April 15.

These are the cultivars that I am growing this year and my observations as of Aug 1.:

Sungold - Slow growing early in season but highly productive by mid-season. Excellent yellow cherry fruit.

Sweet Million - Cherry, Good producer in ground and container.

Viva Italia - Good producer. BER common. Clone in partial shade seems healthier.

Opalka - Caged plant 9 feet tall. Moderate production. BER common.

Purple Calabash - Heirloom. Uncommon vigor. Caged plant is now ten feet tall, 4 feet across at base. Late to flower but now has excellent fruit set. Thriving in heat. Odd shaped purplish green fruit.

Lillian's Yellow - produced only 2 undersized fruit, plant now dying.

Solar Set Hybrid - producing a few medium size fruit with lots of cracks. Plant dying.

Ace 55 - Poor production. Plant dying.

Champion - 20 gallon container grown hybrid. Vigorous. 6 feet tall, good fruit set, large tomatoes not cracking in extreme heat. disease free. Thriving

Patio - grown in 5 gal container. Short thick plant. Seems to thrive in desert heat but requires daily water. good medium fruit. Disease free

I should also mention, to increase fruit set you should shake the plants vigorously at least once a day while they are flowering. An electric hedge clipper in contact with the support structure works well for this job.