Hardone2get, I'll give ya this one, I stand corrected.
Lets go with poorly maintained batteries fail in heat. (Desert Conditions) But even well maintained battery's can fail in cold. That's why all the cold start hoo la. us Marines take care of our vehicles like our rifles, so we check our fluid level in our batteries.

My Grandpa rebuilt battery's as a side job and I helped him. He got old battery's and about 85% of them could be rebuilt for a few dollars and resold. Anyhow you have to maintain a battery. Almost no one does. And that is why the most improvements have been making them more maintenance free, such as Sealed, Gel and AGM. But even they need attention.

Read here and ignore what they say about COLD being hard on battery's.
http://autorepair.about.com/library/weekly/aa101604b.htm
Now, if you do all that, for all your battery's you can be like me, I get twice the life from my battery's in any condition, car, boat, MC, Any battery I can get into I can prolong.
For those of you desert heat guys, I can show AD concerning heat. Shame on Hardone2get U shoulda posted this.
http://www.interstatebatteries.com/cs_estore/content/product_info/battery_testing.asp

Here they talk about corrosion in summers heat concerning battery's.
http://www.automotive.com/auto-news/02/30572/index.html
If you have a proper charger you can stop that by desulfating the battery every 4 months.

Why battery's fail.
http://ecmweb.com/mag/electric_why_batteries_fail/ (Keep fluid in your battery to reduce corrosion)
http://www.mpoweruk.com/failure_modes.htm
Yes they mention heat, But again, you can minimize heat damage buy proper maintenance. I like a wet cell because you can dump the acid and install new acid and gain a lot. (Wash the sediments out of the bottom of each cell.)

Read this but be sure to read the end about murdering your battery (Pre mature death)
http://www.mpoweruk.com/life.htm

Well maintained Battery's do discharge more quickly in cold.
http://chemistry.about.com/od/howthingsworkfaqs/f/coldbattery.htm

And poorly maintained battery's can quickly fail in heat.
AH! Heat is Number one cause of battery failure, but keep in mind it's avoidable.
http://links.exide.com/faq/faq_light_truck.html#heat

Here:
http://www.battery-rechargeable-charger.com/vector-VEC1097A-car-battery-charger.html
Is a good charger that will test/charge and maintain your battery. VEC1092A

If I lived in the desert I suppose I would utilize one of these.
http://www.battery-rechargeable-charger.com/BLS-FAQ.htm

But mostly I would slap it on my Vector once a month and check the fluid level.
(The sealed battery's are not that sealed.) I would desulfate and while I had the battery disconnected i would brass brush every connection from battery to starter and re- install. You desert guys have your work cut out for ya!

With all the problems you list with heat I have determined i cannot afford to retire to AZ like I had been dreaming of since I left Yuma, But...... I hear Darkside tires do very well there May I interest you in the Darkside?
http://lifeisaroad.com/stories/2004/10/27/theDarkSide.html
One tire will replace 4 and with the savings you can buy lots of new battery's. and never have to do battery maintenance at all.

I'm still wondering if this guy figured out if his battery is dead or he has a short.