Hot weather really kicks off on Thursday, August 2. GFS indicates daytime highs up to 47 °C. By Friday, August 3, daytime highs climb to 48 °C. The hottest day is indicated on Saturday, August 4, with temperatures peaking at 49-51 °C! Sunday, August 5, will be slightly less intensely hot, with daytime highs indicated at 48 °C. Recall that this is GFS, with very optimistic highs, but the pattern indicates the hottest day on Saturday, regardless of whether it will go to 47 °C or to 50 °C.
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Peak temperatures across Portugal and Spain from Thursday (August 2) to Sunday (August 5). GFS model guidance. Map: wxcharts.eu.
Keep in mind that this is extremely hot weather which may pose a very serious health risk. Exercise safety precautions for hot weather!