I have recently found out that it is a good idea to prepare for all types of weather for where ever you may be going. While there are usually normal temperature ranges for specific regions, those can sometimes be wrong.
Recently, Europe had one of the worst heat waves in history. In Berlin it got up to 102 degrees. Most advisories told everyone to stay inside, to stay hydrated, and things that mostly come with common sense, but the problem was that not many places in Germany have air conditioning. Even inside in the shade, it was boiling hot for most of the day.
The next week the temperatures in the mornings were down to the lower 50s. Weather is strange and sometimes horrible, but just be prepared for anything, even if you don't think it will happen.