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There are no official easy-to-use recent avr-gcc versions available. The easiest way to work with AVR for Windows is using Atmel Studio, but which forces using a big software solution, or using the outdated WinAVR tools, which is incompatible with more recent JTAG devices such as jtagice3. In addition, most online resources are (partly) outdated, though still useful (See also: http://m8051.blogspot.be/2015/01/avrdude-on-windows-long-time-after.html ). This guide describes how to easily get a more recent version of AVRDUDE working with Windows. Alternatively, you can always compile the most recent version of AVRDUDE yourself (from http://www.nongnu.org/avrdude/ ) but this is a fairly painful process on an unconfigured Windows computer (see also).
There is a recent avr-gcc version compiled for Windows which can be found here: http://andybrown.me.uk/downloads/ .
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