This area is open from April through the end of November. Closed winters because of snow. It's super reliable for soaring conditions and the area management staff is very helpful.
¥2500/day for visitors; ¥500/ride up if you don't top land. Sign in at the 'shop' and don't forget to sign out when you leave.
Check the forecast here: http://weather.yahoo.co.jp/weather/jp/15/5430/15222/9493552.html
Look for south wind becoming northerly or northwesterly with wind speed of 4m or less.
Access
Have to go by car.
Google: Okamidake Camping Ground, Niigata Prefecture
Rules
The flight area is rarely crowded (only on competition days), so there are no specific flight regulations other than
No top landing in strong conditions.
Digital radio: channel 5 (I think)