While summer here in Los Angeles has been fairly temperate – especially for those of us by the beach who get the “June gloom” most mornings – in the rest of the country, the heat index has flown off the charts. Record high temperatures have been set with a disturbing regularity in May, June and July, and triple-digit temperatures have routinely been hit. So it’s no surprise that 2012 is so far considered the warmest year in US history:

The first six months of 2012 accounted for the warmest January-through-June period on record for the contiguous U.S., the National Oceanic and Atmospheric Administration (NOAA) announced Monday.

The national temperatures averaged 52.9 degrees — “4.5 degrees above the long-term average,” NOAA said in a statement. “Most of the contiguous U.S. was record and near-record warm for the six-month period, except the Pacific Northwest.” East of the Rockies, 28 states were “record warm,” NOAA said.

The past year also registered as the hottest 12-month period on record in the contiguous U.S., narrowly surpassing the mark set last month, NOAA said.

You can see the “out of sight, out of mind” dynamic at work when belief in global warming spikes in the summer months and then recedes in the winter. But if you look at these things in a sustained way, you’ll see that the planet is warming, and while weather isn’t climate, it’s reflected in the temperature as well. I’m sure a few snowstorms in January will disabuse everyone of this notion, but it will nonetheless remain true.

Incidentally, as a consequence of all this hot and mostly dry weather (56% of the contiguous US is experiencing drought conditions), 1.3 million acres of forest burned this June from wildfires in Colorado and elsewhere in the US. So when you hear anyone talk about how we must prevent the future impact of climate change, that’s actually wrong. We’re feeling the effects right now.