Harsh weather can be a huge risk on projects. And it is best to mitigate the effects of adverse weather by including a bad weather day reserve in your Microsoft Project schedule.
Adverse weather is both impactful and common on projects. The temperature simply dropping below 32°F can halt concrete installations. And rain or snow can suspend work for days or weeks. Adverse weather is also very difficult to predict. One year the site has record snowfall the next year is a completely dry winter. How can schedulers plan for adverse weather conditions that effect the implementation of the project schedule?
It is not possible to predict with certainty which days in your schedule will become adverse weather no work days. Bad weather planning is a difficult task. But a weather day reserve may alleviate some of the negative effect of inclement weather.
This article demonstrates a Microsoft Project schedule including an adverse weather day reserve to mitigate the effects of inclement weather.
We want to model an adverse weather day reserve in our schedule. But how many days should be included as bad weather days? For this answer we turn to the National Oceanic and Atmospheric Administration (NOAA), which provides inclement weather data.
NOAA weather data supports the generation of a monthly adverse weather day forecast. NOAA provides temperature, rain, and snow predictions by regions, which can be used to formulate tabulated adverse weather days by month. It is beyond the scope of this article to detail the retrieval and transformation of NOAA temperature, rainfall, and snowfall data into predicted regional adverse weather tables. But what you want and what is typically provided on Government contracts is a monthly forecast of adverse weather similar to Figure 1.
We have in Figure 2 our demonstration Microsoft Project schedule.
This is a simple project with three deliverables Demolition Piping, Installation Piping and Quality Assurance Piping. It also has three main activities Remove Damaged Piping, Install Piping, and Inspect Installed Piping. The April 1st start date of the project is a concern; April is a very rainy month.
So, we want to consider rainy weather in our schedule duration. From our Monthly Forecast of Adverse Weather we find that 7-days of adverse weather is predicted during the month long duration of our project, which is significant. We want to include a seven day rainy day reserve in our schedule.
We proceed in Figure 3 and insert a seven day duration Adverse Weather Reserve task to the end of our project.
Select the information icon, Figure 4, to begin the process of assigning the bad weather reserve task a predecessor.
Make Inspect Installed Piping a predecessor with a Finish to Start (FS) relationship, Figure 5.
Now double click on the Gantt chart on the relationship line connecting Inspect Installed Piping and the project end date, Figure 6.
Then in the task dependency dialog delete the FS relationship, again, Figure 6. Highlight the End Project task and, again, select the information icon to insert a predecessor for End Project, Figure 7.
Make Adverse Weather Reserve the predecessor with a FS relationship, Figure 8.
The completed schedule is displayed in Figure 9.
The seven day Adverse Weather Reserve is a painful addition to our month long Pipe Installation project, but it will mitigate the impact of inclement weather during the rainiest month on the calendar. Yes, our project that was scheduled to conclude on April 30th now finishes on May 9th, not ideal, but a reasonable compromise to curb the effects of bad weather.
However, the May 9th completion is the worst case predicted weather impact on the schedule. And, yes, it is realistic that the weather is tempered and few rainy days occur. This becomes welcome good news for your Pipe Installation project.
The way the Adverse Weather Reserve works is for every day outdoor construction is lost and the schedule delayed because of rain, we, accordingly, shorten the duration of the Adverse Weather Reserve task. As additional no work rain days occur we continue to shorten the duration of the Adverse Weather Reserve task. This process continues until adverse weather days deplete the Adverse Weather Reserve task duration.
Bad weather is a hard to predict impactful risk. An Adverse Weather Reserve task included in your Microsoft Project schedule helps to plan for the predicted worst case scenario. Yes, it will lengthen your project. And in our demonstration it extended the project finish date by seven days, which was painful. But including the April rainy day reserve provided the schedule a better opportunity to complete on time or even ahead of schedule. Yes, it is possible that weather is agreeable and the project completes early.
Regardless, the rainy day reserve baked in to your schedule, during the planning stages of the project, warns stakeholders early on of the reality of adverse weather’s potential effect on your schedule. Some have included rainy day reserve days as randomly selected non-work days in the Microsoft Project calendar. We prefer the Adverse Weather Reserve task approach because it is more transparent, which your stakeholders will appreciate.