00:00This weekend, it's going to get really, really arctic once again.
00:03This is going to be the most intense shot of frigid air,
00:07and it's going to be accompanied by the gustiest winds across the Great Lakes and to the east coast.
00:12And so it's going to feel very harsh here, certainly dangerous cold into the weekend
00:17across many parts of the east here with AccuWeather real field temperatures
00:22at the level where just 15 minutes outside in some areas or less
00:28can be a problem from a frostbite perspective.
00:31Dangerous cold pouring way all the way out of the Arctic,
00:35surging across parts of Canada and into a direct express into the eastern part of the United States.
00:41And, John, this winter's cold is not just dangerous, but it's also expensive cold.
00:46So we're always in the world of weather forecasting, but also weather statistics.
00:50We need to be able to quantify what we're talking about and how that affects people.
00:54So can you talk about a weather variable that may not be so familiar to the public
00:58in terms of heating degree days?
01:01Well, people have noticed that their furnaces have been running on extra overdrive here
01:05to keep up with heating homes and businesses here over the recent weeks,
01:10and that is going to result in increased costs for people and businesses in terms of that heating cost.
01:16And one of the ways that we can quantify that is by looking at what meteorologists refer to as heating degree days,
01:21which is a measure of the demand of energy that's needed to heat homes and buildings.
01:27We're going to show you how to compute that.
01:29But the heating degree days can be summed up over any period of time.
01:34It can be looked at for a specific cold wave, a month, or over the entire season
01:38to describe how much heating demand is needed.
01:41And there we have the big equation.
01:43We've got a big font.
01:44I know when I see fine print, I begin to think things are complicated.
01:48I know there's a little bit of math.
01:49We don't like to show too much math on the air, but really this is not that difficult of a calculation.
01:54We're looking at how the day's temperature compares to 65 degrees.
01:58So can you walk us through this here, John?
02:00And 65 is a base that can be used in terms of describing when heating would be needed in some homes
02:06with more insulation that you could look at a 70 degree base or 68 degree base, things of that nature.
02:12But basically you take the day's high temperature and the day's low temperature,
02:17you add them together and divide by two.
02:20This is what meteorologists refer to as one of the ways to describe the average temperature of the day.
02:26So once you have that, you then take 65 minus that number,
02:30and that comes out with the heating degree days for that day.
02:32All right, so there you go.
02:33So if your high temperature is 35, your low is 15,
02:37that gives you a mean temperature, an average temperature for the day of 25 degrees.
02:41That's 40 degrees off from 65, so you're going to need to use a lot of heat to heat your home with that.
02:47And we can, as you said, add these together for multiple days, multiple weeks for a whole season
02:51to give us a big number.
02:53How are we doing this year, and how are we doing specifically over the past three weeks?
02:57Well, let's look specifically at the time period that the most intense cold wave here,
03:02between January 15th and February 8th,
03:04and take a look at a variety of cities here from the northeast to the south.
03:09And these are the sum of the heating degree days during that time period.
03:13And then we compare it to the historic average, the long-term historic average.
03:17And you can see that the heating degree days during this cold wave
03:20have been anywhere from about 115 percent to 150 percent of the historic average.
03:26So that means that the heating demand, on average,
03:29will be 125 percent more than the historic average during that time period in Philadelphia, for example.
03:37And the way you can compute this is if you take your energy bill from last year, for example,
03:41the amount of money that you spent on heating your home or business.
03:45And let's take a look at New York City, for example.
03:47Say you spent $300 during that time period last year.
03:51Well, you'd be spending another $51 in addition to that.
03:55This year, based upon this cold wave.
03:57So when you look at the numbers,
03:59some families are based on their location and the specifics of how they heat their home.
04:04Some people are going to be spending $100 or more extra this year during this cold wave
04:11in order to be able to heat their homes.
04:13And that's another impact to people's bottom lines.
04:17And certainly that's been in the news here,
04:19as we've been talking about the affordability of many things across the country.
04:23And then if we were to compare the entire heating season so far,
04:27going back to September to now,
04:29compared to maybe last year for the same time period, how are we doing?
04:34Well, it's a mixed bag in some areas.
04:36You can see that over the cold season last year in some places,
04:41like for example, Chicago,
04:42there were actually a higher degree of heating degree days during last year during that time period.
04:48But when you compare it to the long-term historic average,
04:51you notice that you're near or just below in many spots.
04:55And that's because other parts of the cold season have been not as cold.
04:59So the intense cold wave has made up for some of those times where the heating demand wasn't as needed.
05:05So in many spots, like New York City and Philadelphia,
05:08you're running about the historic average for heating degree days
05:11in terms of the cold season so far when all things are considered,
05:16even though it's been a really intense period of cold in these locations over recent weeks.
05:21And we're not done yet.
05:21We have another month plus, a couple months to go until the whole heating season is over.
05:26But we're beginning, beginning after this cold weekend,
05:29to see our way out of the coldest of the cold, at least climatologically.
05:33AccuWeather Chief Meteorologist John Porter.
05:35Thanks again, John.
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