i've been riding my recumbent in relatively dry conditions (new bike for me as of february) but am starting to see rust on bits of the chain.

i've been using dry lube regularly (from old mountain bike days)--should i switch to the oily stuff?

it's stored in shed outside -- western nc -- moist out here , but doesn't get direct rain on it.

mm

Sounds like flash rust, very thin layer of rust that will likely disappear with
a little lube and riding. It does suggest need for more frequent lubing
however. I sometimes get this after cleaning bike and chain and let the
bike sit to dry out the chain before applying lube.

It's not being rained on, but the high humidity is almost as destructive. I think I'd be considering a wet-type lube. I really don't like oil but it sure protects in damp/wet conditions.

Dry lube are no good if there is any hint of moisture around, Prolink is good and not to messy once you have wiped it after the first couple of rides, but any decent brand will sort it out pretty fast.

Pedro's Ice Wax, FTW

I've given up on dry type lubes. If it gets rainy or highly humid they can't protect exposed metal (chain) from rust. Unprotected steel will rust above 40% humidity. My advice is to replace the chain and use an oil based lube from now on. Keep the old chain around, and drop it into a can of motor oil as an emergency replacement chain. With chains I'm a bit crude. I use John Deere hydraulic oil on all the various chains I have on bikes and implements around the farm. Yes there are some specific chain lubes that work marginally better, but they cost an arm and a leg. PS, John Deere hydraulic oil is a combination transmission fluid and hydraulic oil. It isn't pure hydraulic oil. Also it takes a couple of washings to get it out of cotton.