Saturday was the warmest day in New York since I bought my iPhone. It was also the day when my iPhone developed a dead zone.

That means that right now, my iPhone is one step away from being a $500 brick. I can receive calls — if the touchscreen is locked, that is — but I can’t make them. Nor can I send SMS, check my email, or use the Safari browser.

Here’s what happened: After returning from a dinner party in an apartment without air conditioning, I attempted to reply to a friend’s SMS message. I touched the text-entry line at the bottom of the display, which should bring up the keyboard, allowing me to enter my own reply. But nothing happened — the keyboard did not appear. I hit the “up one level” button below the display — the one which always takes you to the home screen. On the home screen, I touched the phone icon, but nothing happened. Nor did anything happen when I touched any of the other icons in the “Dock” at the bottom of the display (Mail, Safari, and iPod).

I rebooted twice and restored once to no avail. Then I hit Google and found the link at the top. The funny thing about my dead zone is that the affected region of the display still recognizes dragging, i.e. when I unlock the phone or answer a call when the phone is locked. It just doesn’t recognize a touch.

I’m off to the Apple Store tomorrow to try to sort this out. I’ll post an update once I’m back.