The 1 in 10 days of air temp <0 = 12 and the actual days = 15, so 3 days can be considered in any assessment. For the snow days 1 in 10 = 3 and the actual is 5, so 2 days could be considered.
The days (dates) are the same for both measurements.
Are they assessed as 3 days for the air temp plus 2 days for the snow or are the 3 air days only to be considered as they form the largest difference between actual days and 1 in 10?
Great question. Firstly I would say it is the cumulative effect of the weather in a month you would be assessing as a single CE.
Secondly - I think you might be suggesting a too simplistic answer in terms of how it is assessed. The fact that you have had three days of air temperatures less than zero does not mean you move Completion Date by three days. You have to demonstrate the effect that the three extra cold days had on the project overall (and over and above the first 9 days of cold weather). The two days extra of snow might have had much more impact that the extra three days of cold temperature.
As you will see in other discussions within this group it is relatively easy to confirm that a weather compensation event has occurred, It is much more difficult (and subjective) to prove what the extra over effect of that bad weather has resulted in.