Tilted fibre Bragg gratings (TFBG) are used as sensors in the measurement of many physical and chemical quantities. Measurement is performed indirectly by analysing the power of light transmitted at a specific wavelength or in a selected range of light wavelengths. The wavelengths to be used are chosen arbitrarily by the researcher. However, a change of parameters of the TFBG grating requires reselection of the wavelengths to be used in the measurement. Due to the fact that the TFBG spectrum most often shows the most significant sensitivity to changes in the measured parameters in the cladding mode range or a shift of the Bragg resonance, these are most often used in measurements. The need for human selection of the wavelength range to use was the motivation to undertake research into a method for automatic feature extraction of the TFBG spectrum. The method is designed to enable the identification of the cladding mode minima, the range of wavelengths at which they occur, and the wavelength at which the Bragg resonance occurs. In addition, the heights of the cladding mode minima and the Bragg mode were calculated. The developed algorithm detects key features of TFBG transmission spectra for both P and S polarisation. It automatically identifies the cladding mode range, including their minima and maxima. Furthermore, it allows the determination of the position and height of the Bragg mode for TFBGs with tilt angles up to 6 degrees. The present solution is a pioneering work providing a basis for automating the selection of wavelength ranges or spectrum features for use in TFBG-based sensors.