
The middle latitudes (mid-latitudes, sometimes midlatitudes) are between 23°26`22` North and 66°33`39` North, and between 23°26`22` South and 66°33`39` South latitude, or, the Earth`s temperate zones between the tropics and the Arctic and Antarctic polar regions. Weather fronts and extratropical cyclones are usually found in this area...
Found on
http://en.wikipedia.org/wiki/Middle_latitudes

The latitude belt roughly between 35 and 65 degrees North and South. Also referred to as the temperate region.
Found on
http://www.avon-weather.com/glossary.html

With specific reference to zones of geomagnetic activity, 'middle latitudes' refers to 20 deg to 50 deg geomagnetic.
Found on
http://www.encyclo.co.uk/visitor-contributions.php
No exact match found.