"The world economy is being slowed down by weakness in emerging economies, and the level of world trade is below-average," said Jörg Zeuner, chief economist at government-owned development bank KfW.
He added that late school holidays in Germany's economically strongest states could also have had an impact on the statistics.
But compared with the same time last year, exports still look set to break 2014's record, with five percent more sold in August 2015 than August 2014 at €88 billion.
Germany sold 6.6 percent more goods abroad in the first eight months of 2015 than in the same period in 2014.
Exports to other EU countries outside the Euro, such as the UK and Poland, grew especially strongly at 8.1 percent.