@drt_80 looks like you'd have a circular reference by pointing to B8. It also looks like you've duplicated the calculations. Perhaps you started down one path and then went down another? You could circumvent the circular reference by putting the upstream calculations in the formula itself, but I wouldn't suggest that here because of the number of calculations you're performing, the formula would get very messy very quickly.
From a quick view it looks like you're trying to calculate a number of "available" work days which takes into account weekend, rain, cold, and wet days, including holidays. There are also areas for calculation failure. The most obvious is calculating February to have 28 days, which is hard-coded. You could probably do without the 'DO NOT TOUCH' sheet entirely I'd suspect, as well as consolidating some of your other ranges of data. I would suggest you look at your logic of rain/cold/wet days (it may be what you want, given the margin of error, I just don't know your model well enough to know its accuracy).
My suggestion is to go back to the drawing board and define what it is you're trying to do and build a model which supports your inputs and outputs as desired. My guess is this started out much simpler and was built upon without full knowledge of the end product, thus hampering 'good' design.
