I can't believe how much my car hates warm air. A couple weeks back I tried a little warmer air by flipping around the Civic snorkel thing so it sucks air from behind the radiator instead of behind the headlight. I have about half the radiator blocked (guage reads exactly the same as before), but the air can't be very hot.
Anyway, it worked fine during cold weather, but when it gets over 70 it'll ping like crazy at high throttle settings. Doesn't matter the RPM. I flipped it back and it works fine again. This is a dead stock D16z6, and I checked the timing not long ago. I'm glad I tried the free/simple path before something more elaborate.
I had the same problem, so I just went up an octane level in the Winter, and then use Premium in the warmer months. The cost-benefit ratio may vary, but it's worth it for me. I max out at 160F, and I had pinging at around 110-120F, so I'm guessing that's where you were at.