Swift light curve of NGC 3227 from March 2018 to end of 2019. The dashed black line in the bottom panel indicates the average quiescent hardness ratio (HR) from unobscured data. The dashed line in red is the HR limit for triggering, above which significant obscuration was predicted according to our simulations. The hardness ratio is defined as (H − S)/(H + S), where H and S are the Swift XRT count rate fluxes in the hard (1.5–10 keV) and soft (0.3–1.5 keV) bands, respectively. The first and second XMM-Newton observations, taken on 15 November and 5 December 2019, are indicated by vertical dotted lines.