I work for a 135 canyon tour operator. This morning while enroute to GCN VFR ATIS reported runway visibility at 1/4 mile due to smoke from forest fires in the area. It was a thin layer of smoke, tower visibility was reported at +10 miles. The Captain and I discussed what our options were. Special VFR or analternate? Just after that a new atis came out with the vis at 3 miles. I looked it up after the flight and I jut want to make sure I have interpreted everything right.

Standard VFR flight visibility requirement in class D is 3 miles. Special VFR requires 1 mile. 91.205 states that for special VFR the ground visibility must be atleast 1 mile. If the ground visibility is not reported then flight visibility may be substituted.

So my conclusion is; that when ground visibility is reported at less than 1 mile and everywhere above 50 feet it's clear and a million, even if you have the runway in sight and determine that flight visibility is atleast 1 mile you can not land VFR.

Is that correct?