Error Parsing Weather File

If you are trying to upload a custom weather file and get the "Error Parsing File" message, it's possible the formatting for your weather file doesn't match what HelioScope is looking for. Everything in the weather file you are uploading needs to be in the exact right format, or you will get an error message. In many cases, it is easier to take the critical columns from your weather file and paste them into a weather file known to upload into HelioScope. Below are the steps to get your weather data into a working weather file. 

Step 1: Download this Sample Weather File (CSV)

Step 2: Use Excel to copy the following values from your weather file and overwrite the sample weather file. Be sure to leave row 2 (the column headers) unchanged.

General Weather File Fields

The first row in the sample weather file contains information about the weather file. The most important fields to update are Timezone (UTC), Latitude, and Longitude (Column D, Column E, and Column F), so the weather file shows up in the correct location with the correct Time Zone. Below is a list of all seven fields in the first row of the sample weather file.

File ID File Name State (Abrv.) Time Zone Latitude Longitude Elevation

Standard Values

The sample weather file contains a total of 70 data columns. You can ignore the vast majority of the columns and just update the fields that affect performance modeling in HelioScope. Below is a list of the four most important fields to update for simulating performance in HelioScope:

  1. Global Horizontal Irradiance (GHI) - Column E 
  2. Diffuse Horizontal Irradiance (DHI) - Column K
  3. Dry Bulb Temperature (Ambient Temperature) - Column AF
  4. Windspeed - Column AU

Optional Values (set cells to 0 if unavailable)

The columns below are not required to run a simulation, but feel free to enter them if you have them:

  1. Direct Normal Irradiance (DNI) - Column H
  2. Albedo - Column BJ
  3. Dew Point Temperature Column AI
  4. Relative Humidity - Column AL
  5. Precipitable Water - Column BD

Step 3: Clean up the CSV file before saving

Excel's date formatting can break the weather file parser. You will need to make sure it is in MM/DD/YYYY format before saving. 

  1. Select Column A from Row 3 through Row 8762
  2. Click the Formatting Dropdown and select More Number Formats
  3. Under Custom manually enter "mm/dd/yyyy"
  4. Click OK and save the file

Step 4: Clean up the file in a text editor

Excel is not a perfect tool. It leaves behind metadata when you save a CSV.  Below is a snapshot of the first line from the original sample weather file compared to the first line when we save in excel:

As a result, the last step in preparing a weather file for uploading is going in and reversing the metadata that Excel adds to the weather file. Thankfully, there are only two simple things we need to change to get the file to upload cleanly:

  1. Put quotation marks around the file name (in this case "Seattle_SA_TimeSeries")
  2. Delete the line of commas following the last number (elevation of 61 in this case)

Below is the cleaned up result, you can see that our new Seattle formatting matches the original sample file:

NOTE: If your file name contains a non-english letter, such as Ó or ü, those complex letters will break the uploader. Change them to their non-accented counterpart and the upload should work correctly.

Step 5: Save and upload your new weather file

Woo! You did it! Head over to the  Weather File Uploader and watch the blue progress bar pat you on the back. For more information on how to use the weather file uploader, please read our weather file upload help doc