a–i, SST anomaly time series are shown for each of the locations in Fig. 3. Daily data are shown as lines and vertical bars depict monthly data. MHWs defined from the daily data (using a 90th-percentile threshold, a five-day minimum duration and at least two days separating distinct events) are shown as red lines. MHWs defined from the monthly data (using a 90th-percentile threshold and a one-month minimum duration) are shown as purple bars. The SST anomaly thresholds used to define MHWs in each location are shown as red dashed (daily) and purple dotted (monthly) lines, which are often overlapping.