the weather has been bad this year making the operations difficult for the canadian and danish researchers. their working area on the ice has for long periods been hidden in fog and low clouds, making it impossible for them to fly. of 31 possible flying days with the helicopters, they were only able to fly five full days and five partial days.

How would the previous sentence be correctly capitalized?
The weather has been bad this year making the operations difficult for the Canadian and Danish researchers. Their working area on the ice has for long periods been hidden in fog and low clouds, making it impossible for them to fly. Of 31 possible flying days with the helicopters, they were only able to fly five full days and five partial days.