Lucky is she who can get away in Sepember! The kids are back in school, and the work has piled up after a long summer break. But if you can, this is perhaps one of the best months of all for travelling, because the heat of the summer months in southern Europe and the Eastern Med will still be lingering, but the crowds will have thinned out and the prices will be slashed. The Fall colours of the landscape, too, offer a spectacular backdrop in many parts of the world.
For lingering heat and warm seas head for the Eastern Mediterranean. There's still alot of heat stored in the rocks over there. The Turkish resorts around Dalaman and Bodrum will offer gorgeous weather and good prices in September, as will Greek islands like Crete and Santorini and Rhodes, and the resorts in Cyprus. Malta is heavenly, as is the Algarve, on the other side of the Med. For landscape, try the Czech Republic or Hungary or Slovenia, which offer wonderful walks and cycle ways in stunning Fall landscapes.
The Canary Islands are still warm, and the Red Sea resorts are positively hot. For something more adventurous, head to East Africa, and the great Migration of wildlife in Tanzania and Kenya. Further East, south east Asia is generally a disaster destination in September - in mid monsoon - but Australia, even in the north, is still generally dry. It's a great month to visit South America - particularly Brazil and Northern Argentina - which offers warm conditions and low rainfall in September.
September is one of the best times of year to visit Bolivia.