I should add that cilantro's relative, flat leaf italian parsley, is not having this issue!

It's pretty much the same for me in Denver with our intense sun. I just let it bolt and add some of the coriander to my salsas (also use store cilantro for the leaf and color). It adds some of the flavor of homegrown fresh, since store cilantro isn't always great.

Have you tried snapping off the flowers as they form?

Not a whole lot you can do. Plant it in the shadiest, coolest spot possible. Mist it frequently to keep it cool. Mulch the soil with straw or any other organic mulch to keep the soil cool. Seed frequently and harvest frequently.

It does take some experimenting i find. My method may not be conventional but i get what i need in fresh abundance. I don't have a pic of my cilantro and basil bed...
But for visuals, here is my mesclun bed. About 2 and 1/2 ft square. I plant thick. This is way thick but last years seeds i thought may not be so viable. This is about 10 days...i'll start cutting for young greens next weekend...started a few more varieties under the slats last weekend...provides shade and keeps rainstorms from trashing the young seedlings.

Cilantro and basil both have the same set-up. In a bed just behind me in this pic...
A shade frame similar but attached and has corner feet to raise it up...
Also planted rather thick but once cut it comes back for another round or two...and let a thin row bolt to seed, then save the seeds for next year...
Basil i just plant the entire square with a half dozen varieties and always gives a good show...clip the tops when they try and flower...they keep growing all summer.

If you have an international market, you can get seeds for cheap in the spice section in large bags...crush half of them and seed some whole un-crushed...they will grow at different rates and give a succession crop.
(i'm not so great at explaining but i'll take pics next weekend...)
plant thick=no weed competition

Thank you all for the input! My herb gardening is all about containers, so I've planted some more cilantro and put the container in the shadiest spot I could. Hopefully this time it grows enough to get a respectable harvest before bolting! At least I'm trying! If not, then it may have to be store or farmers market cilantro in my salsa. :(

Angie

Harvest what cilantro you can then chop it up and freeze in ice cube trays with water. Allow the cubes to thaw and drain the water before using the cilantro in the salsa. While it's not fresh, it's pretty close.

Rodney