Looks dodgy. Rain forecast all day in Kusatsu and 9 degrees, so probably 4 or 5 at the top of that pass.
Maybe best to stay closer to home. Chance of rain early on but cloudy mostly. A climb of Hikarigahara? 0 to 1000m....
Glad you made it safe and sound.
The road up to Shiga Kogen is the Olympic road right? The one that goes round and round like a helter skelter? Crazy fast on the way down. Don't risk it!
Glad you checked out Tsubame too. Did you check out the free onsen in the rocks? Yes, the concrete sections are a real bone shaker even on the way up. Just before Tsubame, there is a fork in the road. You can come down that way to avoid the concrete.