Went though there yesterday from Toolangi end to Whanregawen via Black Range. Was mostly dry until the north end which had some recent rain and was slightly damp. Didn't notice any real bumps, potholes or cobbles
Toolangi SF is actually quite a large area from the Healesville/ Yarra Glen end in the south to the Goulburn Vly https://bit.ly/3kVVrHl
It also spans at least 2 distinct weather zones....the southern being the slopes of the Melbourne "Basin"....the other anything north of the "first-line-of hills" (i.e. Toolangi/ Healesville, The Slide, Black Spur etc.
Then there are micro-climates around Mt. St. Lenoard (wet/ foggy/ etc), around Yea (copping it from the south / Melba Hwy as well as west/ Goulburn Valley, resulting in thunderstorms/ showers when all else is dry.
A soggy, grey day in Melbourne's East often is a bright, sunny affair north of Kinglake.....returning from the dry north around Mansfield one often can cop a fairly decent thunderstorm/ shower around Yea, just to turn overcast but dry further south towards Kinglake or Flowerdale.
Ride it often enough...and the pattern will confirm over and over.