Ethiopia or Uganda? July or October?

I'm expat living in Sudan.

I will have two two-weeks holidays:
first starting on 1st July and then secend holiday starting on 15th October.

One of these holidays I would like to use for visiting Ethiopia, another one for Uganda. And here I would like to ask you for advice - which time is better for visiting Ethiopia - July or October? Taking under consideration climate - rain season... As I have little time I plan visit only north of Ethiopia (Bahir Dar, Gonder, Simien NP, Axum, Lalibela areas) and Addis Abeba.

For Uganda - I still don't have plans, but for sure I would like to visit national park with gorillaz... still I'm waiting for Bradt's bookguides - then i would know more...

Mut my question is: which time is better to visit those places?
Ethiopia in July and Uganda in October or the opposite?

Mirka