It’s beginning to look a lot like … summer?

It’s beginning to look a lot like … the warmest Houston December on record.

Average temperatures measured at George Bush Intercontinental Airport over the first 20 days of the month were the warmest since the National Weather Service began keeping records around 1889, local meteorologist Jimmy Fowler said.

And the coming days are looking toasty, too, with highs of 79 and 80 forecast for Christmas Eve and Christmas Day, respectively.

The whole month offers a reminder of the warmer, weirder weather climate change is expected to bring. Average temperatures are predicted to continue to get hotter, and extreme high temperatures are predicted to continue to get higher.

“With climate change, we are experiencing on average not only warmer temperatures but also extremes of temperatures,” Fowler said, “and so we will get these periods where we get into these abnormally, extremely high temperatures.”

But this December weather is proving even warmer than the most dire average temperature climate predictions, said John Nielsen-Gammon, the state climatologist. The amount by which it’s been warmer than normal here is on track to beat any other month.

Normal daily average temperatures for this month, which are calculated based on data from the past three decades, range from 58 to 55 degrees. On several days this December, averages have been more than 20 degrees above that.

The daily average measured at IAH for the whole month, based on the current forecast, may turn out to be about 12 degrees above normal, Nielsen-Gammon said. Currently, the warmest December on record is 1933, when the average temperature was 64.4 degrees, or 9 degrees above normal.

“It’s going to be a warm Christmas,” Nielsen-Gammon said.

There are some meteorological explanations for this, and some randomness to it, experts said. But human-driven climate change, spurred by the burning of fossil fuels, is certainly contributing some to this month’s warmth. Average temperatures have already heated up compared with a century ago, bringing consequences with it.

Surface ocean temperatures have also been abnormally hot, another trend expected as the globe warms.

“It’s been a weird, weird month,” said Matt Lanza, meteorologist with Space City Weather.

Lanza hadn’t forgotten the day early on this December, when the maximum temperature hit 87 at Hobby Airport, a harbinger of what was ahead. Record high temperatures continued to be broken. Other parts of the region and state also experienced warmer-than-normal weather.

Across the country, headlines told of other strange weather, including high winds in the Colorado Rockies and deadly tornadoes in the Midwest.

In Houston, the weather seemed locked into a warm pattern, Lanza said. No one should be waking up Christmas morning expecting snow. Or ugly sweater weather. Or hot chocolate drinking temps.

On Wednesday afternoon, three friends finished up their ice cream and reflected on how they were used to bundling up at least a little bit when the Christmas lights appeared. Houston was hot — but not this hot.

It was a common theme among questioned passersby: This is Houston! We have crazy hurricanes! And awful winter freezes! Still some did concede 80 degrees felt strange.

Linda Beitler had kids swimming in her pool.

“It’s been really warm,” her friend Robbie Morrison said. “Hot as a matter of fact.”

The two were catching up over coffees, hot for Beitler and iced for Morrison. Mannequins in the shopping center around them wore sweaters and light puffer coats.

People walking by had on T-shirts. emily.foxhall@chron.com