A wearable thermometer patch for continuous wearing by a user includes a circuit substrate that includes an electric circuit, a battery holder mounted in the circuit substrate, and a detachable cover layer on the battery holder. The battery holder can hold a replaceable battery to supply power to the electric circuit. A temperature probe unit in connection with the electric circuit includes one or more temperature sensors in electric connection with the electric circuit in the circuit substrate. The one or more temperature sensors each can measure temperatures near the users skin to produce one or more temperature values.
