Multiwavelength light curve of PKS 1510−089 during the May 2015 flare. From top to bottom: nightly gamma-ray flux above 150 GeV from MAGIC (the dashed line shows the average emission in Feb.−Apr. 2012, Aleksić et al. 2014); Fermi-LAT flux above 0.1 GeV in 6 h binning, and the corresponding spectral index (the dashed line shows the average emission from the 3FGL catalog, Acero et al. 2015); X-ray spectral flux (filled circles) and spectral index (empty circles) measured by Swift-XRT; polarization percentage and polarization angle measured by NOT, Steward, Perkins, RINGO3, AZT-8, and LX-200 (see legend); optical emission in R band (KVA, SMARTS) and UV emission in w2-band (Swift-UVOT); IR emission in J band (SMARTS, MIRO-NICS, TCS); radio observations by Metsähovi at 37 GHz. Data from IR to UV are corrected for Galactic absorption. The red and blue shaded regions show Period A and Period B, respectively, for which the spectral modeling is performed.