Volume 28, number 1, June 2014

Using our New Simplified Weather Data Calculator

Most people would agree that the crucial factor for heating calculations is the outside temperature.

In order to provide better analysis tools for key players in the energy sector, the DATECH Group, in partnership with the NGTC, has come up with a bin data and degree‑day calculator for most cities in Quebec.

At the moment, degree-days are only available for Montreal and Quebec City. While we do have access to accurate data on a number of cities in Quebec and Canada, without a specialized tool it is difficult or impossible to obtain up-to-date bin data.

Gaz Métro’s DATECH Group is proud to have developed such a tool.

With the use of a reliable weather data source and an effective compilation tool, calculations can now be performed with greater precision.

The following is a user guide for the simplified weather file.

System settings

First, make sure the comma has been set as the default decimal symbol in the “Region and language” option in your settings.

Choosing a weather station

For reliable, standardized results, weather data must be downloaded from the Government of Canada website (http://climate.weather.gc.ca/).

The calculator is designed to compile hourly data from all Canadian weather stations. In some cases, a search will turn up a number of different stations to choose from. As an example, we will use the MONTREAL/PIERRE ELLIOT TRUDEAU INTL station, which comes up when a search is performed for Montreal.

Selecting and downloading data

From the page displaying the weather station data, select the desired months one by one. The hourly data downloaded in CSV format will be for the active month (in parentheses). The day of the month will not affect the content of the downloaded data.

Once you have selected the desired month, save the CSV file in a folder intended for weather data. Do not modify the name of the CSV file. Repeat this step for each of the desired months from this weather station.

Hourly Data

This is the most time consuming step for a first-time user of the tool; however, once the data from the main weather stations has been archived, it will only require updating in the future.

Sorting data

You can group together as many CSV weather files as you want within the same folder, as long as they are generated from the same weather station. Once you have selected a start date and folder, the macro will automatically generate the 12 files for the year in question.

Compiling data using the calculator

First, make sure there is no data in the calculator. Click on the “Erase all” button to set the calculator back to the default settings.

Next, select the first month of the desired time period. We will use the period from September 2012 to October 2013 for the MONTREAL/PIERRE ELLIOTT TRUDEAU INTL weather station as an example. Enter the first month of the time period, then click on “Automatic selection” in the “Results” tab. Next, select the folder containing all the CSV files.

Once the data has been compiled, you can substitute the equilibrium temperatures in your guide to obtain the correct degree-days.

Excel file

Excel file

Excel file


Missing data

Some data may not be available for certain months. This is the case at MONTREAL/PIERRE ELLIOTT TRUDEAU INTL for June 2012, for example. The letter “M” appearing in the Temp oC column means that the data is missing.

Hourly Data

Missing data will obviously have an impact when the calculator is used, as the degree-days for the months in question will be displayed as zeroes. To prevent this, click on “Nearby stations with data” option.

Hourly Data

This will allow you to select the closest available station to the initial station in order to fill in the missing data.

Station Results - Advanced Search

Compiling data

During the automatic selection of data, it is very important to select the month of January for the desired time period. According to the naming protocol for the CSV files, the January file will appear at the top of the list.

Please note that this tool will be available on the Partenaire en ligne site with the other calculation tools provided by the DATECH Group.

Please do not hesitate to contact us (DATECH@gazmetro.com) if you encounter any issues when using the tool or if you have any improvements to suggest.

Sami Maksoud, Eng. M.Eng., CMVP®
Relationnal and Energy Efficiency Advisor