I live in Eugene, Oregon and go to Bandon at least once a month, and have been going there regularly since 2004.
Sometimes, it's not what time of year to go for calm weather, but time of day, especially in summer.
This year, January was awesome, shorter days, but absolutely great weather.
This year the spring was the wettest in memory as was the the fall of 2010.
However, "the secret to Bandon is that it is built on sand". It is always playable except when you have snow that stays, or in a tournament where the rules dictate fairness for all.
The weather forecast can be irrelevant in Bandon, but if you are not there to witness it, then you were not there.
Plan for the worst, and hope for the best.
Personally, I like the early summer with long days of easy an 36 holes.
For playing into or against the wind, I like to use percentages for distance, like today at Turtle Bay, it was a 25% wind for distance, add 25% distance into and subtract 25% with it.
Thanks