Fundamental Principles of Weather Mitigation

Contractors must often work in unfavorable weather. Two important questions arise. How much labor inefficiency will be incurred (which leads to the question of how much should the estimate be increased) and how can the negative impacts be mitigated? This paper addresses these two questions. The literature is reviewed and data from multiple projects are examined to estimate the average loss of efficiency resulting from very hot and very cold temperatures and from rain and snow. The average loss of efficiency estimates are used in a simple example to illustrate how to decide how much to increase the workhour estimate to account for adverse weather. Fundamental principles are stated so contractors can mitigate the effects of unfavorable weather conditions. It is postulated that if the principles are followed, labor inefficiencies resulting from weather-related disruptions are less likely to occur.