Below-zero temperatures returned to the county overnight, dipping to 4 below in the hours before daybreak.

And while there was no talk of a polar vortex, the low readings did recall the 9-below thermometer readings and 35-below wind chills of two weeks ago.

One of the big differences this time around was the relatively light winds.

The only sub-zero wind chill readings came at 7 p.m. at 6 below, before dipping to 10 below at 9 p.m. and 11 below an hour later.

The air temperature dropped below zero at 2 below at 2 a.m., and further fell to 4 below for several hours starting at 4 a.m. But winds were calm during this period.

The average temperature range for this time of year is a high of 36 and a low of 21.

The record low readings for Jan. 20, 21 and 22 all came in 1885 — 18 below, 18 below and 20 below, respectively.

The low temperature readings at 6 a.m. today provided a chilly send off to seven busloads of people who rode to Washington, D.C., to march in a March for Life rally on the 41st anniversary of the Supreme Court's abortion rights decision in Roe v. Wade.

Butler County rally organizer Gretchen Cararie said the group was expecting to be outside from 11 a.m. to 4 or 5 p.m. The group not only had cold weather to contend with, but also upward of 7 inches of snow that fell Tuesday in Washington.

Others who have to work in the cold said the key is thinking ahead and dressing appropriately.

Tad Kelley, a spokesman for the U.S. Postal Service said letter carriers are advised to wear layers of clothing to stay warm during the hours they are walking their routes.

“They shouldn't wear anything too tight, as that can keep moisture against their bodies,” he said. “That is the best way to stay warm.”

Builders also layer their clothes to stay warm, but too many layers can hamper a worker's movements on the job site.“People are all bundled up, which makes it harder to work, and makes us less productive,” said Charlie Chambers, production manager at Dan Ryan Builders, which has homebuilding projects in Cranberry Township. “We probably lose half of our productivity (because of extreme cold).”On some sites, if the home has been framed, Chambers said, those working outside can sometimes move inside to get away from the elements and still be able to get some work done.He also said the cold prevents workers from using concrete.Cranberry Township's public works employees also layer their clothing, but sometimes need the added help of a heated bus to get out of the harsh elements, particularly when working on such projects as a broken water line.Peoples TWP advises workers to be aware of symptoms of hypothermia and frostbite, and how to avoid furthering problems. It also advises them to dress in layers, to try to avoid walking on slippery surfaces and to carefully shovel snow and remove snow from vehicles.Pennsylvania American Water also educated employees about frostbite and hypothermia. Spokesman Gary Lobaugh said, in weather like this, the company tries to limit outdoor work to emergency repairs only.“If we do send employees out we make sure they have the necessary cold weather gear and that they take frequent breaks to get warm and keep their body hydrated,” he said.Eagle staff writers John Bojarski, Will DeShong, Bob Schultz and Kim Paskorz contributed to this report.