Even by Houston standards, this year has been hot.

The average 2017 temperatures so far for the Houston area have been the warmest since record keeping began, according to the Houston/Galveston office of the National Weather Service. Despite an unusually cool May, average year-to-date temperatures have broken records at all four of the office’s “climate sites”: Houston (Hobby), Houston (IAH), Galveston and College Station.

The changes have been particularly stark in Galveston, where average temperatures have climbed almost four degrees in the last 19 years, from 66.3 in 1999 to 69.7 this year.

By contrast, temperatures for Houston have only risen two degrees since 1927, from 65.2 to 67.2. (The Houston measurement has been recorded at various sites over the decades and is now made from Intercontinental Airport.) The government has been monitoring Houston-area weather for almost 150 years. The first climate site was in Galveston, in 1874.

Despite some cooler May temperatures, the year to date average temperatures are the warmest on record for our four primary climate sites. pic.twitter.com/FTppzEgY7H — NWS Houston (@NWSHouston) May 16, 2017

Kent Prochazka, a meteorologist with the National Weather Service in Houston, said he and his colleagues first started noticing the unseasonably warm weather in November.

“Certainly by January it was really obvious,” he said. “[The Gulf of Mexico] just didn’t cool down like it normally does.”

The culprit, Prochazka said, was southerly winds. They encased East Texas in humidity for much of the winter, preventing the air from cooling at night.

While the Houston area still got a few cold (or cool) fronts, he said, winds from the south were more persistent than usual.

Houston’s warm winter fits with a nationwide trend that’s hit the Midwest and the South particularly hard. From Brownsville to Minneapolis, temperatures were about four to six degrees above normal, according to data from the National Oceanic and Atmospheric Administration.

The East Coast didn’t fare much better, where temperatures were about two to five degrees above average. The only places with cooler than average weather were small patches of Idaho and the Pacific Northwest.

Prochazka worried about the warm, wet air in the western and Caribbean parts of the Gulf of Mexico. The conditions were perfect of tropical storms. He was unsure whether there would be more hurricanes — or whether the unseasonable warmth was linked to climate change — and he didn’t want to speculate. But these conditions, he said, meant the storms that did hit could be worse.

Hurricane season usually starts around June. In April, however, Tropical Storm Arlene surfaced in middle of the Atlantic Ocean, making it about 500 miles west before dissipating 24 hours later. It was one of the earliest Atlantic storms since the 1950s or ‘60s, when researchers started tracking hurricanes with satellites, Prochazka said.

“It should be noted, however, that this type of storm was practically impossible to detect prior to the weather-satellite era,” he added. “You would’ve had to have a ship basically run into it.”

Don’t board up those windows just yet. The Tropical Meteorology Project, a program by Colorado State University, has predicted lower-than-average hurricane activity in the Atlantic for 2017. Researchers predicted there would be 11 named storms, four hurricanes and two really big ones — that is, hurricanes of Category 3 intensity or higher.

Prochazka said he couldn’t attest to the findings of the Colorado State study. The National Oceanographic and Atmospheric Administration, where he works, will release its own estimates later this month.

