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Quick Start Overview Degree Day Products Printing Reports More Information


Quick Start
Overview

This web site provides access to thousands of daily maximum and minimum temperatures for 14 cities in the state of Wisconsin, USA. Detailed reports are available by month from September 1990 to the present. Reports are available about one month after the last day of the report month. Use the Data Status page to determine the most recent month available. The following cities are represented:

ARLINGTON ASHLAND BELOIT EAU CLAIRE
GREEN BAY HANCOCK LA CROSSE LANCASTER
MADISON MARSHFIELD MILWAUKEE RHINELANDER
SPOONER STURGEON BAY

This Web site uses Microsoft's Active Server Pages to render the reports and an Active Data Object connector to access the Microsoft SQL Server 7.0 database where the maximum and minimum teperatures are stored. Instead of storing thousands of HTML pages for years of weather data, this Web site creates the Web pages on demand.


Degree Day Products

Heating & Cooling Degree Days Daily Average Temperatures Growing Degree Days
HDD and CDD with Adjusted Balance Point Normal Temps & Degree Days Download Normal Temps in CSV Text Format
Download Max & Min Temps in CSV Text Format Heating and Cooling Degree Days Zone Summaries


1-Heating & Cooling Degree Days

To create a Heating & Cooling Degree Days report, select city (weather station), month and year. Then click the Submit button at the bottom of the page.

Heading titles used in the Heating & Cooling Degree Days report:
Day Day of the month
Max Maximum temperature for the day
Min Minimum temperature for the day
Avg Average temperature for the day
HDD Heating degree days
CDD Cooling degree days
Cum Daily cumulative degree days for the month

Summary titles used in the Heating & Cooling Degree Days report:
Avg Average temperature for selected month
Norm Normal temperature and degree days for selected month
Dep Positive or negative departure from monthly normal
Max Maximum temperature or degree days for selected month
Min Minimum temperature or degree days for selected month

Refer to both the heading and summary titles when reading the summary values at the bottom of the report.


2-Daily Average Temperatures

To create a Average Daily Temperatures report, select city (weather station), month and year. Then click the Submit button at the bottom of the page.

Heading titles used in the Average Daily Temperatures report:
Day Day of the month
Average Temp Average temperature for the day

Summary titles used in the Heating & Cooling Degree Days report:
Avg Averages for selected month (refer to column headings)
Norm Normal temperature for selected month
Dep Positive or negative departure from normal monthly temperature
Max Maximum temperature for selected month
Min Minimum temperature for selected month


3-Growing Degree Days

To create a Growing Degree Days report, select city (weather station), month and year. Then click the Submit button at the bottom of the page.

Heading titles used in the Growing Degree Days report:
Day Day of the month
Max Maximum temperature for the day
Min Minimum temperature for the day
Avg Average temperature for the day
Growing 40 Base Growing degree days computed with a base of 40
Growing 50 Base Growing degree days computed with a base of 50
Corn Grow 50/86 Corn growing degree days computed with a minimum base of 50 and a maximum base of 86
Cum Daily cumulative growing degree days for the month

Summary titles used in the Growing Degree Days report:
Avg Averages for selected month (refer to column headings)
Norm Normal temperature and degree days for selected month
Dep Positive or negative departure from monthly normal
Max Maximum temperature or degree days for selected month
Min Minimum temperature or degree days for selected month

Refer to both the heading and summary titles when reading the summary values at the bottom of the report.


4-HDD using adjusted Balance Point
5-CDD using adjusted Balance Point

Heating and Cooling Degree Days Using Adjusted Balance Point

Some applications like home energy audit systems require using a base cut-off temperature other than 65. This feature allows you to adjust the "balance point" to match these unique requirements. You can also use adjusted cooling degree days as growing degree days for points other than the 40 and 50 that is provided by the Growing Degree Days product.

The slide at the lower-left corner of the input form allows adjustments from 55 - 80. Be sure to select item #4 for adjustable heating degree days and #5 for adjustable cooling degree days. Adjustable heating and cooling degree days are displayed on separate reports.

To create an Adjusted Heating & Cooling Degree Days report, select HDD using Adjusted Balance Point or CDD using Adjusted Balance Point. Then select city (weather station), month, year and Balance Point. Click the Submit button at the bottom of the page to display the report.

The report headings and interpretation are very similar to Heating & Cooling Degree Days.


6-Normal Temps and Degree Days
7-Download Normal Temps in CSV Text Format

Normal temperatures and degree days represent the latest 30 year averages available from the National Oceanographic and Atmospheric Administration for the fourteen Wisconsin cities available at this site. These averages are used for determining the departure from norm in the other reports.

To create a Normal Temps and Degree Days report, select Item 6, the city and press the Select button.

To download Normal Temps and Degree Days in comma seperated values text format (a CSV text file), select Item 7, the city and press the Select button. Field names are contained in the first row of the data.


8-Download 1 Month of Daily Maximum and Minimum Temperatures
9-Download 12 Months of Daily Maximum and Minimum Temperatures

To download maximum and minimum temperatures select the city (weather station), month and year. Select Item 8 for 1 month of data or Item 9 to download 12 months of data, then click the Submit button at the bottom of the page. Field names are contained in the first row of the data. Less than 12 months of data may be returned of you select a date less than a year before the most recent month available for your selected station. Use the Data Status page to determine the most recent month available.


10-Heating Degree Days Summary
11-Cooling Degree Days Summary
12-Pop Weighted Heating Degree Days Summary
13-Pop Weighted Cooling Degree Days Summary

Heating and cooling degree days zone summaries are available for eleven geographic areas in Wisconsin that experience very similar temperatures throughout the year. A population weighted State average is also available when you select the Pop Weighted reports.

If you do not live close to one of the fourteen available weather stations provided here, you can use the zone summaries with some assurance that the heating and cooling degree days are representative of normal terrain areas in your area.

The following table depicts the weather stations used for zone reporting. Notice that Zone 3 is listed twice. That is because Zone 3 is an average of both Rhinelander which is inland, and Green Bay on the shores of Lake Michigan. (Zone 3 does not have good full time weather stations and is influenced by both cold inland temperatures and maritime weather from Lake Superior and Lake Michigan).

ZONE Wx STATION
1 ASHLAND
2 RHINELANDER
3 RHINELANDER
3 GREEN BAY
4 SPOONER
5 MARSHFIELD
6 GREEN BAY
7 EAU CLAIRE
8 HANCOCK
9 LANCASTER
10 MADISON
11 MILWAUKEE

To create a Heating or Cooling Degrees Zone Summary report, select month and year and click the Submit button at the bottom of the page.

Population Weighted (Pop Weighted) Zone Summaries use the a ratio of the latest available population counts in the zone to total State population to calculate the State Population Weighted Heating and Cooling Degree Days.

A map of Wisconsin degree day zones is available from the menu bar.


Printing Reports

From your Web browser select File | Print to print a displayed page.

All report products can be printed on a single 8 1/2 x 11 inch portrait sheet if the top and bottom margins are not too big and the text size is set to medium. Select File | Page Setup and set all margins to .5 (1/2) inches. If the page is still printing on two pages instead of one, decrease top and bottom margins or the text size until the report fits onto one page.


More Information

What is a Degree Day?
Degree Day is simply a way of measuring how hot or cold it has been over a 24 hour period. Whenever the average, (or mean) temperature is below 65 degrees Fahrenheit, you have a heating degree day. Whenever the average is above 65 degree Fahrenheit, you have a cooling degree day.

If in a 24 hour period the high outside temperature was 70 degrees and the low was 50 degrees, then the average temperature for that day was 60 degrees - halfway between 70 and 50 degrees. This is 5 degrees less than the base temperature of 65. Therefore we can say that there was 5 heating degree days for the period.

if in a 24 hour period the high outside temperature was 80 degrees and the low was 60 degrees, then the average temperature for that day was 70 degrees - halfway between 60 and 80 degrees. This is 5 degrees more than the base temperature of 65. Therefore we can say that there was 5 cooling degree days for the period.

There is a direct relationship between heating degree days and the amount of energy required to heat a residence. The higher the heating degree days, the higher the fuel bill to heat a typical home. The opposite is true for cooling degree days. Once the daily average temperature is above 65, homes start using air conditioning. Higher cooling degree days means the air conditioner stays on longer to keep the residents comfortable resulting in higher cooling costs.

What is Average Temperature?
Average temperature is the maximum and minimum temperatures for the day divided by two and rounded to the nearest degree. At .5 the value is rounded up.

What is Growing Degree Days?
Growing degree days use the same formula as Cooling Degree Days, but uses a base cut-off temperatures lower than 65. The base depends on the crops that are grown in the area. Corn growing degree days is a bit more complicated in that corn growth in Wisconsin stops if the temperature never reaches 50 or remains above 86, and has various values when the max and min are between 50 and 86 Fahrenheit. This system presents a report for 40, 50, and corn growing using 50 and 86. Other growing degree days can be calculated by selecting CDD Using Adjusted Balance Point.

Growing Degree Days base 40 calculation
gdd = Growing Degree Days
average = maximum + minimum temperature / 2
gdd = Round( average - 40)
if gdd < 0 Then
gdd = 0
End If

Growing Degree Days base 50 calculation
gdd = Growing Degree Days
average = maximum + minimum temperature / 2
gdd = Round( average - 50)
if gdd < 0 Then
gdd = 0
End If

Corn Growing Degree Days calculation
Low = Low temperature for the day
High = High temperature for the day
cgdd = Corn Growing Degree Days
If Low <= 50 AND High <=50 Then
cgdd = 0
End If
If Low > 50 AND High > 50 Then
If High > 86 Then
cgdd = Round((Low + 86)/2 - 50)
Else
cgdd = Round((High + Low)/2 - 50)
End If
End If

If Low <= 50 Then
If High > 50 AND High <= 86 Then
cgdd = Round((50 + High)/2 - 50)
End If
If High > 86 Then
cgdd = Round((50 + 86)/2 - 50)
End If
End If
if cgdd < 0 Then
cgdd = 0
End If

Degree Day Database Tables
Each station record contains the maximum and minimum temperature in degrees Fahrenheit (F) for each day. The database also contains the 30 year normal maximum and minimum temperature for the same stations. This allows reporting of the departure from normal for: