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<p>Accurate precipitation estimation with weather radars is essential for hydrological and meteorological applications. The differential reflectivity (<span class="inline-formula"><i>Z</i>_DR</span>) is a crucial weather radar measurement that helps to improve quantitative precipitation estimates using polarimetric weather radars. However, a system bias between the horizontal and vertical channels generated by the radar produces an offset in <span class="inline-formula"><i>Z</i>_DR</span>. Existing methods to calibrate <span class="inline-formula"><i>Z</i>_DR</span> measurements rely on the intrinsic values of the <span class="inline-formula"><i>Z</i>_DR</span> of natural targets (e.g. drizzle or dry snow) collected at high elevation angles (e.g. higher than 40<span class="inline-formula">^∘</span> or even at 90<span class="inline-formula">^∘</span>), in which <span class="inline-formula"><i>Z</i>_DR</span> values close to 0 dB are expected. However, not all weather radar systems can scan at such high elevation angles or point the antenna vertically to collect precipitation measurements passing overhead. Therefore, there is a need to develop new methods to calibrate <span class="inline-formula"><i>Z</i>_DR</span> measurements using lower-elevation scans. In this work, we present and analyse a novel method for correcting and monitoring the <span class="inline-formula"><i>Z</i>_DR</span> offset using quasi-vertical profiles computed from scans collected at 9<span class="inline-formula">^∘</span> elevations. The method is applied to radar data collected through 1 year of precipitation events by two operational C-band polarimetric weather radars in the UK. The proposed method shows a relative error of 0.1 dB when evaluated against the traditional approach based on <span class="inline-formula"><i>Z</i>_DR</span> measurements collected at 90<span class="inline-formula">^∘</span> elevations. Additionally, the method is independently assessed using disdrometers located near the radar sites. The results showed a reasonable agreement between disdrometer-derived and radar-calibrated <span class="inline-formula"><i>Z</i>_DR</span> measurements.</p>