I remember getting to Altona (MQSM) and not being able to feel my fingers. Really struggled to brake, and shifting not much better.
On another ride, I also remember the sweat stinging my eyes on exactly the same corner.
+1 to The Duckmeister's recommendation. But, it's good to start thinking about these things early. Arm/leg warmers and/or headsweats will surely come up on the online sales, and/or in your LBS's bargain bin, sometime between then and now.
Oh. And merino first layer. Almost always.