A mass of arctic air is on its way to Portugal, starting to arrive from tomorrow (Tuesday). While ‘spring’ officially arrived on Sunday, Tuesday will see the country plunged backwards when it comes to temperatures. IPMA (meteorological institute) is estimating falls in the region of 4º-6º for maximum temperatures, and of 5º – 6º for minimums. Areas like Serra da Estrela could even see some snowfall. The worst of the temperature change will be felt in the north and centre, with the south (Algarve) coming off best.