Add a Weather Period to a Risk

Add weather periods and non-working estimates for each period to model the impact of your weather risks. Because weather risks are seasonally-dependent, you can more accurately describe a risk's potential impact by varying non-working estimates across multiple weather periods. For example, a frozen river is more likely to occur in the coldest winter months, preventing deliveries by ship from arriving on time. You may choose to define that event as a weather risk with monthly non-working estimates that increase as the weather becomes colder.

Non-working time estimates for a risk are defined as either distributions of non-work days or as a percentage of non-work days within the weather period. When defining estimates using percentages, you will also estimate the percentage of non-work days that will immediately follow another non-work day. This is known as persistence.

The definition method you choose depends on the data available to you for the weather event you want to model. If your data shows past weather occurrences as a range of days, consider estimating non-work time using a distribution. If you have data that has been recorded daily, or is measured in percentages over a period of time, it may it may be more accurate to estimate non-work time using percentage and persistence values.

To add a weather period to a risk:

  1. In the object selector, select ﱆ Project or Program, and then select a project or a program from the list.
  2. From the Main Menu, select Risk, and then select Risk Register.
  3. In the table, select a risk with a Type of Weather, and then select the Weather detail window.

    Note: Weather data is not supported for risks with a type of Threat or Opportunity. To add a weather risk, see Add a Risk to the Risk Register.

  4. In the Non-Working Time Definition list, select one of the following values:
    • Distribution: Each period's non-working time values will be estimated in days.
    • Percentage: Each period's non-working time values will be estimated as the percentage of non-working days during the period.

      Note: You can modify this option at any time, but existing non-working values will be removed.

  5. Select Add.
  6. Complete the following fields for the weather period:
    • Period Name: The name of the period.
    • Period Start: The start date of the period.
    • Period Finish: The finish date of the period. Period dates cannot overlap. There can be gaps between periods if you anticipate periods without non-working time, such as the summer season.
    • If you chose a Distribution non-working time definition, complete the following fields:
      • Distribution Shape: The probability distribution that best models the estimates for non-working days in the period. Valid values are Triangle, Uniform, and BetaPert.
      • Minimum Days: The minimum number of non-working days in the period.
      • Most Likely Days: The most likely number of non-working days in the period. This is only available if you selected a Triangle shape.
      • Maximum Days: The maximum number of non-working days in the period.
    • If you chose a Percentage non-working time definition, complete the following fields:
      • Non-Working Percentage: The percentage of non-working days in the period.
      • Non-Working Persistence: The probability of a non-working day following another non-working day in the period.
  7. Select Save.

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