We bought some at the yard last summer and painted them in gloss, have weathered over winter fine. They do gloss for outdoors I think but we used stuff that mums school had bought to paint their doors etc
Primer, undercoat & exterior gloss & you'll get a good resiliant finish. You could save a lot of time & effort though by using plastic pole sleeves.
We just used whatever we found in the garage - some of it was gloss, some emulsion, some fence paint for the rustic poles.
The poles seemed to weather well regardless of the type of paint.