I have a less excentric answer:
The ITCZ causes much more TS and rain over the African mainland than over the Arabian peninsula. Coming closer towards the Indian subcontinent, the influence of monsoon streams are of more importance for the correct interpretation of weather information.
Thus we could assume that the ITCZ is very important over Africa, while in other regions it is less. The same applies for the Americanas. It 's clearly marked over the Carribean Seas.
Any suggestions?
Dani