Next week, mainland Portugal will experience a significant heat event, mirroring broader trends across much of Europe. The Portuguese Institute for Sea and Atmosphere (IPMA) has confirmed forecasts of very high temperatures, with Lisbon expected to reach around 37°C and inland regions, particularly the Alentejo, potentially exceeding 40°C. However, the agency is pushing back against alarmist predictions circulating online that suggest temperatures could hit 50°C.
What to Expect: Temperatures and Warnings
Meteorologist Paula Leitão, speaking to Euronews, stated that “it is very likely that yellow or orange warnings for high temperatures will be issued for the whole of mainland Portugal.” Such warnings can only be issued a maximum of 72 hours in advance, so official alerts will come closer to the weekend. The heat is expected to begin on Saturday 20 July, with a gradual increase through Sunday and into the following days. In the Alentejo and other hot spots, temperatures could approach 43°C.
The areas most affected are those that typically suffer the worst heat: the entire Alentejo region, the Tagus Valley (especially the districts of Castelo Branco and Santarém), and the Douro Valley. In major cities, Porto should see highs between 30°C and 33°C, while Lisbon will exceed 35°C. The official designation of a “heatwave” can only be confirmed later, as it requires at least six consecutive days with temperatures at least five degrees above the 30-year average within a 15-day window.
IPMA’s forecasts cover a 10-day period, and Leitão noted that while the weather will remain hot from Saturday onward, there may be a slight downward trend on Thursday and Friday. The agency’s recommendations are standard: pay attention to children and older people, seek cool places, avoid sun exposure and strenuous work during the hottest hours, and stay hydrated.
Rejecting Alarmist Forecasts
Despite the seriousness of the heat, IPMA is actively dismissing exaggerated scenarios that have spread on social media, with some users predicting record temperatures of 50°C. Paula Leitão insists that the forecast values “are far from the record figures for mainland Portugal, which are 46 or 47 degrees.” She attributes the misinformation to the democratisation of meteorological forecasting tools: “In the past, only national weather forecasting centres had access to the data. Today, the models that run internationally have open data and anyone can go and look for them. So someone with a bit more training in meteorology can interpret that information and say what they have understood. The models have no filters to carry out a critical analysis of the values they produce. And there are a lot of models. Some are better than others, and 10-day forecasts are highly uncertain.”
Leitão is categorical: “Temperatures of 50 degrees or more have never been recorded anywhere on the Iberian Peninsula.” The message is clear: yes, it will be very hot, and weather warnings are likely, but people should take necessary precautions without panic. As she summarises, “we need to wait and see whether we really are facing absolute record highs, which at the moment is not what we are expecting.”
This heatwave comes as Europe faces broader climate challenges, with tropical nights posing hidden health risks across the continent. For Portugal, the focus remains on practical advice: keep hydrated, avoid going out during the hottest hours, take care of the most vulnerable, wear light clothing, and avoid exertion. Above all, do not believe everything you read on the internet.
