Colours of Aviv (Flag pair - Standard)

The first month in G-d's calendar is Aviv (also called Nisan following the return from the exile in Babylon).  The colours associated with Aviv are dark red and sky blue.  The colours come from the tribe associate with Aviv - which is Judah, and Judah was symbolised by a garnet or blue topaz on the breastplate of the Cohen Gadol (the High Priest).

When looking at the scripture references for the breast plate and the names of the stones, even the Temple Institute recognises that there is uncertainty about the exact order of the stones and the exact meaning of the names of the stones (thus making sometimes a variety of stones and their colours possible interpretation).  The Temple Institute is the most orthodox authority to research the ceremonial requirements for temple service.  Therefore the association of a stone with a tribe and hence the stone's colour needs to be received by faith, which even the Temple Institute needs to accept.  

Being led by Ruach HaKodesh (Holy Spirit) we concur with the scriptural recognition that the order of the tribes and their association with certain months of G-d's calendar follows the order of the tribes in the camp in the wilderness - that means after G-d's people had left Mitzrayim (literally tight spot, blockage i.e. captivity, confinement, Egypt), G-d ordered them to camp around the tent of meeting in a defined way.  In that order, Judah was the first tribe because Judah was responsible for worship which needed to go ahead of all other tribes.  This is why we associate Judah as the first tribe with the frist month of the year, Aviv, and take the colours for the month from the stone by which the tribe of Judah was represented.