NEC ECC: Adverse Weather Claim

Currently working on an NEC3 project that has suffered with poor weather affecting productivity etc. As a result, weather data has been collected from the Met Office.
The data shows that in some months both the Monthly Rainfall Total & Total Days of rain > 5mm has triggered the 1:10.
Other months have only triggered the Monthly Rainfall Total, how is it possible to demonstrate / calculate the affected duration?

Firstly you have to notify within 8 weeks of becoming aware of the event. In simple terms this should be within 8 weeks of the end of the calendar month that the weather occurred in. You cant really say “i was not aware for 8 months as I didn’t bother to get the records until then”.

Then you have the difficult job to prove the effect the extra over weather had on your programme which is never straight forward and likely to be subjective. You just have to try to be as clear as possible.

In truth at the month where you had bad weather, you should have update your programme and seen that planned Completion was running late. At that stage you should have tried to prove that it was down to the bad weather.

It is easy to prove that a weather event is a compensation event. Much harder to definitively prove the impact that the extra over weather had, compared to the up to 1 in 10 year event which is Contractor risk.