Afterhours volatility at 1AM when few are watching October 25
"The last day of trading for expiring VIX options is the end of regular trading on the day before (typically Tuesday). Expiring VIX futures on the other hand trade in extended hours trading until 7:00 AM ET on the day of expiration (typically Wednesday).Jul 29, 2018" source: sixfigureinvesting.com/2010/01/vix-option-expiration-dates-2010/