From October through December 2011 U.S. airlines achieved their best domestic on-time performance for a fourth quarter since then U.S. Transportation Department began keeping comparable records in 1985, with an on-time arrival rate topping 85%, newly released DOT statistics show.

The DOT counts a flight as on time if it arrives within 15 minutes of schedule.

The airlines are benefiting in large part from weather so unseasonably mild that Weather.com declared in a news article last week: “The most obvious story about the winter of 2011-2012 is that there is no winter.”

But the high on-time rate of 85.1% still provides a boost to the image of the industry, with Airlines for America highlighting the statistics with a self-generated story on its website. The on-time performance was so high, the story notes, that there is only one quarter in any season that topped it: an 85.2% rate in the third quarter of 1991.

The statistics released by the DOT on Feb. 14 also show the highest on-time performance for any December in the past 17 years, at 84.4%. That compares to an average of 71.5% for December in the previous 16 years.

The December rate for domestic flight cancellations, at 0.75%, was well below the average of 2.7% for December in the past 16 years and the lowest for any December in that time span.

The on-time rate for all of 2011, 79.6%, was the fourth-highest for any full year since 1985. Hawaiian Airlines ranked first in on-time performance, followed by Alaska Airlines and AirTran Airways.

JetBlue Airways ranked last, at 73.3%. At New York’s John F. Kennedy International Airport, where the low-cost carrier operates the highest number of flights, its on-time arrival rate for the year was just under 75%, according to data compiled using Flightstats.com’s Analytics tool. At Boston Logan International Airport, where it operates its second-highest number of flights, its on-time rate was slightly above 73%.

Of the country’s 29 busiest airports, Newark Liberty International had the worst on-time arrival performance last year, at 66.7%, and in December, at 71.7%.

Aside from on-time performance, U.S. airlines also improved on other service performance criteria in 2011. For example, the number of mishandled baggage reports dropped from 3.51 per 1,000 passengers in 2010 to 3.39 last year. The rate ranged from 1.63 at AirTran to 7.32 at American Eagle.

Similarly, the rate at which passengers were bumped from overbooked domestic flights dropped from 1.09 per 10,000 passengers in 2010 to 0.81 last year.

Even so, the number of complaints that consumers filed with the DOT about U.S. airline service climbed from 9,135 in 2010 to 9,425 last year. The categories in which complaints rose included flight delays and cancellations, refunds, fares and disability.