<p>Parity–time-symmetric systems with loss and gain can be described by non-Hermitian Hamiltonians. In such systems, the inclusion of a nonlinear saturable gain can eliminate the imaginary part of frequency eigenvalues and suppress noise. Consequently, a system biased at an exceptional point can be used to create enhanced sensors. However, exceptional-point frequency sensing typically has a relatively small scaling factor and a limited dynamic range. Here we report a nonlinear parity–time-symmetric system that detects the phase difference between the loss and gain resonators. We show both theoretically and experimentally that the phase difference has a cube-root singularity with a large scaling factor over a wide dynamic range. We create a wearable capacitive temperature sensor based on exceptional-point phase sensing and show that it can measure temperatures from 36 °C to 55.5 °C, which corresponds to a perturbation from 0% to 3.95%, with a maximum normalized sensitivity of 400, an estimated dynamic range of 53.52 dB and an estimated signal-to-noise ratio of 63.8 dB. Compared with an exceptional-point frequency sensing sensor, the sensitivity of our sensor is enhanced by an order of magnitude.</p>