Multi-wavelength light curves around the VHE flare detected by MAGIC in August 2019. The top panel shows the MAGIC fluxes above 300 GeV in daily binning. The dashed curve is a fit of an exponential function using Eq. (1) in order to estimate the variability timescale (see text for more details). The horizontal dashed-grey line represents 4% of the Crab Nebula flux above 300 GeV. The second panel from the top displays the Fermi-LAT fluxes in the 0.3−300 GeV band in monthly binning (dark-yellow markers) and 2-day binning (maroon markers). In case the source is detected with TS < 5, an upper limit at 95% confidence level is quoted. In the third panel from the top are the Swift-XRT fluxes in the 0.3−2 keV (light-green markers) and 2−10 keV (dark-green markers) bands. The fourth panel from the top displays the UV fluxes from the Swift-UVOT instrument in the UVW1, UVM2, and UVW2 filters. Finally, the bottom panel shows the R-band fluxes from GASP-WEBT and Tuorla.