Cumulative Rainfall Less Than Expected

Due to a very dry month this summer, the actual cumulative rainfall (mm) at our project was less than the 1 in 10 year average (mm).

Most weather CEs are due to experiencing ‘worse’ weather with the threshold for the event becoming a CE based on actuals being over and above the 1 in 10 year average. However, the cumulative rainfall weather record has millimetres as its unit of measurement and the condition is ‘difference between’ rather than ‘above’ or ‘below’ thus a CE should be due whether the actual is above or below the average. Given this criteria, unless the measurements were exactly the same, there could be a CE every month but the impact on Defined Cost would vary. The difference between our actual and the 1 in 10 year average is quite large in percentage terms and as this is partially an earthworks and landscaping project, we believe this is worth pursuing.

My question is whether there is a CE due to actual cumulative rainfall (mm) being less than the 1 in 10 year average (mm)?


Hi, good question and the answer is yes, if the value of the weather measurement recorded at the place stated in the Contract Data is by comparison with the weather data shown to occur on average less frequently than once in ten years, it qualifies.
There’s a ‘BUT’.
Each calendar month is measured separately, so if the period spans more than one month it has to be looked at as separate events, you refer to a month so that should be ok.
It has to have occurred before the Completion Date and at the place stated in the Contract Data.
Another ‘BUT’.
If it qualifies with the above then you have 8 weeks to notify it from the end of the relevant month otherwise you will be out of time.
Another ‘BUT’
If you notify in time you will have to demonstrate the effect it had upon the remaining work, it is not sufficient to demonstrate that the event qualifies you have to be able demonstrate the effect it had. You must do this in the quotation for the event - see clauses 63.5 & 62.2, & 63.1 [for the setting of the dividing date NEC4]. If you were not doing any work that would have been affected by the dry spell then there will be no time or cost impact and the Prices and Completion Date will not be changed.
Hope that helps, happy to discuss.