According to the weather reports this summer and into the beginning of fall extremely hot weather is predicted throughout Europe, with the hottest temperatures in the Iberian peninsula. The reports are predicting highs to be into the low 40's Celcius. I would follow this very closely before you go so you pack as little as possible. If the weather is as hot as predicted you certainly will not need anything. If hopefully it cools down you can always buy something along the way.
This is from the Accuweather webpage:
The hottest locations throughout Portugal and Spain will see multi-day heat waves with temperatures peaking at or above 43 C (110 F).
A man cools off in an urban beach at Madrid Rio park in Madrid, Friday, Aug. 3, 2018. (AP Photo/Francisco Seco)
Unseasonably warm nights will also be a concern during these heat waves, making for dangerous conditions as homes without air conditioning that will be unable to cool down before heat builds again the following day.
It will be important for residents and visitors to take extra care in the heat to prevent illness. Drinking plenty of water, spending time in the shade and wearing light clothing will be necessary.
When possible, strenuous outdoor activity should be avoided during the hottest part of the day.
Stagnant conditions contributing to the intense heat will also result in poor air quality, especially in and near cities. Air quality may also be worsened by smoke from wildfires.
Children, the elderly and those with respiratory or cardiovascular health conditions should avoid spending time outside as much as possible when air quality alerts are issued.
Wildfires to threaten Spain, Portugal and the Alps
The intense heat waves and long spells of dry weather throughout the summer will bring a high risk for wildfires to much of western and central Europe.
The areas at greatest risk will be from northern Portugal into northern Spain and from the Alps into Germany and Czech Republic.
A wet winter and spring across much of western and central Europe will result in more vegetation than in previous years.
However, as dry weather prevails early in the summer, the stage will be set for a high wildfire risk during the second half of the season.
Villagers watch a firefighting plane drop water to stop a raging forest fire reaching their houses just a few dozen meters away in the village of Chao de Codes, near Macao, central Portugal, Wednesday, Aug. 16, 2017. (AP Photo/Armando Franca)
The Iberian Peninsula will be at risk first due to building heat in June combined with little or no rainfall.
The threat will spread northeastward across France and into the Alps, Germany and the rest of central Europe from July into August.
This threat is likely to continue into autumn as the dry vegetation and warm weather persist.
"Drought will be an increasing concern across these areas from late summer into autumn, stressing agriculture and water supplies for the second straight year in many locations," Roys said.
Just a word of precaution.