Is Carnarvon, Western Australia Below the 26th Parallel?

Yes. The town of Carnarvon lies at latitude 24.87° South, which is north of (i.e., below) the 26th parallel south.

• Located in the Gascoyne region, at the mouth of the Gascoyne River.
• The 26th parallel south passes through the northern edge of the Shark Bay World Heritage Area, ~150 km south of Carnarvon.
• Climate: Arid subtropical; hot summers, mild winters; major horticulture (bananas, tomatoes, grapes) via irrigation.

"Below the 26th parallel" in Australian context often refers to zones for biosecurity, fishing, or administrative boundaries.