Temperatures are easing already but will plunge on Friday night due to the arrival of a mass of polar air from the Arctic.
Forecasts point to a shift from mild temperatures to a gradual drop in temperature, with "wind intensification, especially on the west coast and highlands," blowing northerly to 50 kmph, with bursts of up to 70 kmph.
According to the Portuguese weather service, on Saturday and Sunday, "maximum temperatures should not exceed 15°C, except for the southern Algarve coast and some Alentejo areas which may be 2 to 3 degrees higher.
The really cold area will be the North and Central regions of the country where the maximum temperatures should be between 5 and 10°C.
“Minimum temperature should be under 10°C and in the order of 0°C to 5°C in the interior regions, where the first frosts of the season are foreseen," says the weather service.
The Algarve’s highs and lows for the next few days, as predicted for Faro, are 16-22°C on Friday with the certainty of rainfall, 11-10°C on Saturday with zero chance of rain, 8-16°C on Sunday and then a gradual easing of the cold spell through next week until, next Friday, the temperature is predicted to be 12°C at night and 20°C max in the day.
See: IPMA