Years ago, I ate at Sushi Yasuda in New York. After I went, I was reading up on the chef, and an article about him mentioned that he accounted for air humidity while making his sushi rice. Wow! My kind of guy!
There is a 'how much water with your rice' conversation on this site, one that basically said "get a great Zojirushi," but I'd like to hear from an expert sushi rice cooker -- can anyone explain to me a formula or set of considerations for making really great sushi rice? I'm thinking of the sort of thing taught sushi chefs at the Japanese equivalent of the CIA, if there is such a thing.
Here is a link mentioning ambient humidity as a concern for rice cooking: http://firstname.lastname@example.org/msg13272.html