Hot coffee in hot weather

Real summer weather has hit Riga - yesterday and today we have +29 degrees. Some people still prefer coffee instead of cold, refreshing drinks. If you are thirsty, coffee is the least appropriate drink - not only it is hot, but, as one food specialist told me - it is also a dehydrator. But, if you have to deal with papers (analogue or digital) like a woman in picture, you still are after it's caffeine energy dose.