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Charlie
10-13-2007, 01:01 PM
what does it mean when they say cooling degree days or heating degree day

when i listen to noaa weather on a scanner they give the daily report and use this terms

Steve M
10-13-2007, 02:58 PM
what does it mean when they say cooling degree days or heating degree day

when i listen to noaa weather on a scanner they give the daily report and use this terms
Heating and cooling degree days refers to the amount of energy needed to either heat or cool your home. The standard temp used is 65 degrees...the warmer it is above 65 degrees the more demand for cooling, the more energy used for cooling...the colder it is below 65 degrees the more demand for heating, the more energy used for heating. That's my understanding of it but I'm sure there is more to it.

Bill O
10-13-2007, 03:39 PM
That's pretty much correct. It has to do with heating and cooling requirements.

Add the high temp and the low temp for the day and divide by two. That gives the average temperature. If the average daily temp is 60 then you have 5 heating degree days. If its above 65 then you have cooling degree days.

The thought is that above 65 you need cooling and below 65 you need heat. Usually they are added together for a month or season and compared to old data.

I think growing degree days are based on 55F. Its mainly for farmers as certain crops need a certain amount of growing degree days.

Charlie
10-13-2007, 05:04 PM
thanks now i know what they are talking about

Steve M
10-13-2007, 09:31 PM
I think growing degree days are based on 55F. Its mainly for farmers as certain crops need a certain amount of growing degree days.
I know that different varieties of peaches all have different amounts of cold days they need during the winter. The ones requiring more cold days are grown farther north where the ones grown down here don't need so many cold days in the winter.

Bill O
10-14-2007, 07:36 AM
I know that different varieties of peaches all have different amounts of cold days they need during the winter. The ones requiring more cold days are grown farther north where the ones grown down here don't need so many cold days in the winter.

Right, crops/trees need growing degrees days both on the hot and cold side. If you listen to the radio in any agriculture heavy region you'll notice that the weather report is full of growing degree days.

bclark
10-14-2007, 09:14 AM
Anybody have a guess as to how many HEATING degree days the Obs has recorded?

Bill and Jim aren't eligible since I'm sure they know the answer from working up here :p

Steve M
10-14-2007, 09:46 AM
Anybody have a guess as to how many HEATING degree days the Obs has recorded?

Bill and Jim aren't eligible since I'm sure they know the answer from working up here :p
Not without looking it up but I'm sure it out weighs the cooling degree days by at least 3:1

Bill O
10-14-2007, 12:58 PM
Anybody have a guess as to how many HEATING degree days the Obs has recorded?

Bill and Jim aren't eligible since I'm sure they know the answer from working up here :p

From when, July 1st?

Has Mount Washington ever had a cooling degree day? My guess is no, or very few. Its rare that the high temp is above 65, let alone the daily average.

bclark
10-14-2007, 01:22 PM
From when, July 1st?

I'm not sure what you mean by this...I'm talking about the entire 75 year record that the Obs has, if that answers your question.


Has Mount Washington ever had a cooling degree day? My guess is no, or very few. Its rare that the high temp is above 65, let alone the daily average.


There actually has been just one, although I can't recall off the top of my head when it was. Ryan would probably know since he is the one that told me that little tid bit. My guess would be the August 2, 1975 the day that our all time record high was set. Or it could have been either of the days surrounding that day too. I'm not sure, I'll have to get back to you on that....

Bill O
10-14-2007, 01:34 PM
I'm talking about the entire 75 year record that the Obs has, if that answers your question.


Just using estimates I bet I can get pretty close. Normal daily temperature is 27.2F. Although that is the 30 year average.

So 65-27.2 = 37.8 per day x 365 days x 75 = 1.034 million

Now there were a few leap years in there, and I'm also guessing the 75 year average is a little colder than the 30 year average. A million is a good number though.

Brad
10-14-2007, 04:02 PM
Heating oil companies use heating degree days to calculate when you need your tanks filled.

Steve M
10-16-2007, 01:21 AM
According to what I have found, the average heating degree days per year for MW is 14015. So if you multiply that by 75 you get 1,051,125.00. So, Bills estimation is very close. Again, these are averages. The data covers from 1961 - 1990.

http://met-www.cit.cornell.edu/ccd/nrmhdd.html