The bloodsucking insects could be particularly prominent this year, experts claimed, as it was one of the mildest winters for over 130 years when records began.
"A mild winter really helps them," said researcher Sven Klimpel from the Senckenberg institute.
Over the winter, hibernating mosquito eggs are vulnerable to extreme cold weather.
But the insects are benefiting from climate change and the growing lack of differentiation between the seasons, he said.
No larvae have yet been found, said Klimpel, but all it will take is a few warm days of over ten degrees for the hibernating eggs to begin their development.
Exotic insects from the south, which with rising temperatures have been seen moving further north, could add to this year's expected swarm.
Researchers say the Asian bush mosquito has now established itself in Baden-Württemberg, Hesse and North Rhine-Westphalia and also hibernates there over the winter.
The Asian tiger mosquito, which has repeatedly been sighted in southern Germany, but has not yet established a robust presence there, say experts.
"Both will spread across Europe and keep moving north," predicted Klimpel. The fear is that these exotic species could transmit viruses such as West Nile fever or dengue fever.