Lisbon, Portugal is most comfortable in January, February, March. The toughest month for heat is July (comfort 39/100). In August, daytime highs average 29.1°C (feels like 30.5°C) with 9.8 days over 30°C and 4.2 tropical nights.
| Month | Avg high | Avg low | Feels like | Days ≥30°C | Days ≥35°C | Nights ≥20°C | Comfort |
|---|---|---|---|---|---|---|---|
| January | 15.2° | 9.2° | 13.1° | 0 | 0 | 0 | 100 |
| February | 16.6° | 9.9° | 14.8° | 0 | 0 | 0 | 100 |
| March | 17.6° | 10.5° | 16.1° | 0 | 0 | 0 | 100 |
| April | 20.4° | 12.4° | 20° | 0.2 | 0 | 0 | 100 |
| May | 23.4° | 14.4° | 23.6° | 2 | 0.2 | 0 | 97 |
| June | 25.9° | 16.7° | 27° | 5 | 1 | 1.2 | 73 |
| July | 29° | 18.1° | 30.4° | 10.6 | 2.8 | 3.4 | 39 |
| August | 29.1° | 18.6° | 30.5° | 9.8 | 2.6 | 4.2 | 39 |
| September | 25.8° | 17.3° | 26.3° | 2.6 | 0 | 2 | 82 |
| October | 23.9° | 16.4° | 23.9° | 1.4 | 0 | 0.2 | 98 |
| November | 18.5° | 12.3° | 17.5° | 0 | 0 | 0 | 100 |
| December | 15.9° | 10.5° | 14.3° | 0 | 0 | 0 | 100 |
Destinations scoring 75+ for August heat comfort:
It's hot but manageable. August daytime highs in Lisbon average 29.1°C with 9.8 days over 30°C. Plan outdoor sightseeing for mornings and evenings.
Based on 5 years of climate data, the most comfortable months in Lisbon are January, February, March. The toughest month for heat is July, scoring 39/100 on our heat-comfort index.
In August, nights in Lisbon average a low of 18.6°C, with 4.2 tropical nights per month (nights that stay at or above 20°C) — a key factor for sleep quality if your stay has no air conditioning.
Tell us where and when you're going. If a heatwave becomes likely for your dates, we'll email you early — with cooler day-by-day alternatives nearby.