Sunscreen wears off through sweat and hours in the saddle. A long sleeve cycling jersey doesn't, which is part of why it's worth considering beyond just cooler-weather riding, particularly across Australian trails with long exposure to direct sun.
* Fabric weight, breathability
* Fit that doesn't restrict arm movement
* Coverage that holds up over a full day
* Moisture-wicking material for hot conditions
A long sleeve cycling jersey earns its place in a kit for reasons beyond temperature, sun coverage that lasts the whole ride being one of the main ones. Explore the range at Leatt MTB Australia and find a jersey suited to longer days on the trail.