If you are using tags outdoors or in an area where RFID could be subjected to dampness, you should consider using a tag that is made to withstand liquids.
Most RFID tags will temporarily stop reading if their antennas are wet. See How do Liquids affect RFID read ranges? for more information about RFID and liquids. Tags that are built to withstand dampness can be dried and will continue reading as normal.
Recommended tags for wet environments:
NOX-TM4 Metal-Mount RFID Tag is a heavy-duty metal-mount tag. It can be boiled, impacted, or frozen and won't break down.
TX-2 RFID Tag is perfect for shipping requirements. TX-2 labels are made with a synthetic material that is waterproof and chemical resistant.
NOX-1 RFID Tag is a small sized tag made to be scratch and water proof, as well as chemical resistant.