I'll guess that the day the crewman of the RNZAF Iroquois helicopter was winched down to the remains of ZK-SML, the WX was CAVOK?
Probably. The day that the crewman of the RNZAF Iroquois helicopter found himself being winched off a hill, himself seriously injured, the rest of his crew dead due CFIT, was a good day for IFR. 25th April 2010. I imagine he has since queried why they went VFR.