Then again, if you are training in a 2-33, a little rain will probably
increase your performance by washing some of the bugs and dirt off!

Seriously, in a non-laminar wing (any metal trainer, pretty much),
especially if it hasn't been waxed recently (and who waxes a 2-33 or a
Lark!), light rain will have no aerodynamic effect. Biggest problem
will be reduced visibility through the canopy, and less braking action
if you land on grass.

Obviously, stay away from heavy rain showers or thunderstorms, but
pattern-bashing in a light, occasional drizzle beats watching birds
fly.

Good training, too.

Kirk