This can depend on where you are going. In most of the country, the main rainy season runs from June to the end of September, with short rains in March. In the Omo and Mago parks however, in Southern Ethiopia, the seasons are different with the main rains from March to June and shorter rains in November. (However, in a time of changing global weather patterns it is no longer possible to be absolutely definitive about the rains
With the upgrading of the airports along the Historic Route (Axum, Lalibela, Gondar and Bahir Dar), and good road conditions in the country it is now possible to visit the country even in the rainy season. For travellers who do not mind waiting out a downpour (usually followed by brilliant sunshine) there are certain rewards – a green countryside full of crops and flowers and the sites largely to your selves.
Climate and clothing
Because of the elevation, temperatures rarely exceed 250C in most of the country; although in some of the lower lying areas (Awash, the Afar and Somali Regions, Omo and Mago parks, Gambella) it can get considerably hotter.
Pack light clothes for the day time and a jacket or sweater for the evenings, and a good pair of walking shoes even if you are not going trekking – path ways around historic sites are usually uneven and stony. Trekkers in the Simien and Bale Mountains will need warm clothes, water-proofs and 3-4 season sleeping bags. On a cultural note – Ethiopians are generally modest dressers, and visitors should be sensitive about going underdressed (shorts, tank tops and bare backed) into places of worship. Shoes must always be removed before entering churches and mosques.
Health and medical
The possession of a valid Yellow Fever vaccination certificate is no longer mandatory but visitors coming from countries where Yellow Fever has been reported may be asked. (Some countries, such as Australia and Thailand, will ask for a Yellow Fever vaccination certificate if you have visited Ethiopia in the previous 6 months.) Immunisation for Hepatitis A and B, Tetanus, Typhoid and Polio is recommended.
Malaria: in many sites malaria is not a problem because of the elevation – this is true of Axum, Gondar and Lalibela for example, but it can occur in Bahir Dar at the end of the rainy season and after unseasonable rains. Lowland areas along the Awash River, the Omo Valley, Rift Valley and Gambella are subject to malaria outbreaks. Mosquitoes are constantly improving their resistance to the prophylactics on the market, so you should consult your doctor about the prescription. Alternatively, you can keep mosquitoes and other insects at bay with repellent creams and sprays. (Climatic changes and phenomena such as el-Nino has meant the appearance of malaria at unseasonable times, and its spread to areas previously malaria free.)
Visitors should take a simple first aid pack, which would include: different size plasters, antiseptic cream, anti-histamine cream and/or tablets for insect bites, aspirin and/or Panadol, sun barrier cream (while temperatures are moderate the sun is strong) and anti-diarrhoea tablets such as Imodium for emergencies (they will not cure the problem but will control the symptoms).
There are private clinics in most towns, and pharmacies are considerably better stocked than in the past.
Generally, visitors should take out standard holiday health insurance in their home countries.