A sharp rise in temperature is forecast from Saturday. Check your town before making plans
Mainland temperatures are expected to rise quickly from 19 September, with many places above 30°C and the warmest inland areas potentially reaching 38°C.
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Archived 12 September 2026The change matters for outdoor work, sport, travel, children, older people and anyone with a health condition—even if their district is not under a weather warning.
- A warmer, drier continental air mass is expected to raise mainland temperatures from Saturday, 19 September.
- Forecast maximums range broadly from 30°C to 38°C, with the highest values expected in the Alentejo and Tagus Valley.
- IPMA showed no high-temperature warning for mainland districts at the early-morning check on 17 September; warnings can still change.
- Use the current forecast for your municipality and adjust strenuous outdoor plans if the local heat is higher than normal.
What is expected to change
A hot, dry air mass is expected to move over mainland Portugal, producing a marked rise in temperature between Thursday and Saturday. From Saturday, maximums above 30°C are forecast across much of the mainland, while parts of the Alentejo and Tagus Valley may reach around 38°C.
The warmer spell may last for several days and some places may also have unusually mild nights. The national range is not a forecast for every town: the coast, higher ground and northern districts can be markedly cooler than the hottest inland areas.
A forecast is not the same as a warning
At the early-morning check on 17 September, IPMA's high-temperature warning map remained green for mainland districts. That means no warning was active at that time; it does not mean the forecast heat is irrelevant or that the warning position cannot change.
Check the latest IPMA forecast and warning status for the place and day that matter to you. A headline about 38°C should not be applied automatically to Porto, Lisbon, a coastal village or a mountain area.
Plan around the people most affected
The Directorate-General of Health advises people to drink water regularly, avoid direct sun during the hottest part of the day and give extra attention to babies, older people, people with chronic illness, pregnant people and anyone working or exercising outdoors.
If a clinician has limited your fluid intake or you take medication affected by heat, follow medical advice rather than a general hydration rule. Heatstroke is an emergency; severe confusion, collapse or a very high body temperature requires urgent medical help.
What you can do now.
- 01
Check the hourly forecast for your municipality, not only the national maximum.
- 02
Move strenuous outdoor activity away from the hottest hours where possible.
- 03
Check on vulnerable relatives, neighbours or guests during the warmer days.
- 04
Review the IPMA warning map again before a long journey or outdoor event.
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