Best Time To Visit Ethiopia.

Between September to April is the best months to visit Ethiopia. 

Best Time
- October to December (Beautiful scenery, little rain)
High Season
-October to January (Main historical sites and some parks get busy)
Low Season
-May to September (Few travelers and low-season rates)
Best Weather
-October to April (Little rainfall, sunny days)
Worst Weather
-July to August (Wettest months)

For best experience of your holiday, please find below the specific time to travel to such specific attractions:

Northern Historic Circuit and to its Highlands

• The October to February dry season is the best time to plan a trip to the ancient rock-cut churches of Ethiopia's stunning Northern Highlands. However, even during the wet season, rains rarely last all day. If you're looking to save money, consider booking a trip in March or April, when the rains are light and prices for accommodation and tours are generally lower. Usually, it's best to avoid traveling in June and July, when the rains in this region are at their most extreme. 
•  Trekking to Simien Mountains National Park
  The Simien Mountains are a vast mountain range whose highest peak stands at 14,872 feet, making it one of the highest mountains in Africa.  Trekking here is fantastic, not only because of the scenery, gorges, and streams but also because you get a chance to look for endemic wildlife like the Gelada Baboon and the Walia Ibex. The best time to trek is from September to November, when it's dry, green, and relatively dust-free. October, in particular, can be spectacular because this is when the mountain wildflowers are in full bloom.
•  Best Time to Visit the Omo Valley
  With sixteen distinct tribes living in the Omo valley of southwestern Ethiopia, it's a fascinating destination for those interested in African culture. The remote location, which was barely accessible by four-wheel drive, means that traditional customs and beliefs are very much intact and untouched by time for most of these tribes. This region has two rainy seasons, with one lasting from March to June, and a shorter one in November. In some parts during the raining season, access is often impossible during these times, so planning your trip for the dry season is essential.
•  Best Time to Visit the Danakil Depression
  Danakil is one of the hottest places on earth, with daytime temperatures easily reaching 122 degrees Fahrenheit.  It's a fascinating destination where you can witness the age-old tradition of salt caravans, experience Afar culture, and marvel at a myriad of active volcanoes. If you've ever felt the urge to visit another planet, you'll love the extraordinary landscapes of this region. To avoid feeling like you're boiling alive, however, make sure to visit during the cooler months of November to March.
• Ethiopia's Festivals
  Ethiopian festivals are certainly worth planning a trip around. Mostly religious, festivals generally last several days. Orthodox Christian festivals are the most prominent and visible in Ethiopia and are celebrated according to the Ethiopian calendar. For example, Ethiopian Christmas (known as Ganna) is celebrated on January 7, rather than December 25. Enkutatash, the Ethiopian New Year, is celebrated on September 11. If you're keen to experience Ethiopian festivities at their most colorful, consider planning your trip around Meskel or Timkat, but be prepared to book your domestic flights and hotels well in advance.
• Watching Wildlife

Watching wildlife in Ethiopia is not very season dependent. However, July and August are the wettest months and travel over that period isn’t recommended (especially if you intend to do some hiking or camping). Ethiopia’s spectacular scenery is at its best from September to December, when days are sunny, the landscape is green and lush and the sky is free of haze after the rains.