ZAN Controller issued a Visual Approach clearance to a Kenai IFR arrival after the pilot reported the airport in sight; however the weather was reported as IFR; the reporter indicating uncertainty regarding the procedure in question.

Narrative

A C208 departed for Kenai. Kenai Tower called to let R5 know the field was IFR and gave me the visibility and the winds before I was even talking to the pilot. I advised the pilot of the conditions and vectored the aircraft for the ILS approach. The pilot reported the airport in site about 12-15 miles north of the airport. I cleared him for the Visual Approach and switched him to Tower. Then Kenai Tower called R5 to advise us that the field was IFR and the aircraft couldn't have a Visual Approach. The Controller got loud and aggressive on the phone so I eventually gave my initials and hung up. I immediately called the Supervisor over to tell him about the situation and ask what I should do. He told me it is fine as long as the pilot had the airport in site. He then left the area to go look up the information in the 7110.65. I couldn't find him in the area for clarification and Kenai Tower was calling me again. I didn't want to have another confrontation with the Tower Controller before I talked to the Supervisor. The aircraft landed and the Supervisor later told me that he would just be writing up the event as a learning experience for everyone because he didn't even know we couldn't clear a pilot for a visual when the field was reported IFR. I asked several other controllers in the area and there was some confusion on the matter. If a pilot has an airport in site; they should be able to assume responsibility and be given a Visual Approach. Several airports in Alaska don't have up to the minute weather updates and the weather observation isn't always taken at the runway or airport the weather is being reported for. The field could be completely clear with a bank of fog a mile to the side of the runway. The pilot is the one there at that moment with the most up to date conditions and should be able to make the final call for what type of approach he/she wants.