I found the following information at the British Ethiopian Embassy's website.
The Ethiopian New Year falls in September at the end of the big rains. The sun comes out to shine all day long creating an atmosphere of dazzling clarity and fresh clean air. The highlands turn to gold as the Meskel daisies burst out in all their splendor. Ethiopian children clad in brand new clothes dance through the villages giving bouquets of flowers and painted pictures to each household.
September 11th is both New Year's Day and the Feast of St. John the Baptist. The day is called Enkutatash meaning the "gift of jewels." When the famous Queen of Sheba returned from her expensive jaunt to visit King Solomon in Jerusalem, her chiefs welcomed her back by replenishing her treasury with enku or jewels. The spring festival has been celebrated since these early times and as the rains come to their abrupt end, dancing and singing can be heard at every village in the green countryside. After dark on New Year's Eve people light fires outside their houses.
The main religious celebration takes place at the 14th-century Kostete Yohannes church in the city of Gaynt within the Gondar Region. Three days of prayers, psalms, and hymns, sermons, and massive colorful processions mark the advent of the New Year. Closer to Addis Ababa, the Raguel Church, on top of the Entoto Mountain north of the city, has the largest and most spectacular religious celebration. But Enkutatash is not exclusively a religious holiday, and the little girls singing and dancing in pretty new dresses among the flowers in the fields convey the message of springtime and renewed life. Today's Enkutatash is also the season for exchanging formal New Year greetings and cards among the urban sophisticated in lieu of the traditional bouquet of flowers.
Timket, or Epiphany falls on January 19th, just two weeks after the Ethiopian Christmas. It is actually a three-day affair, beginning on the Eve of Timkat with dramatic and colorful processions. The following morning the great day itself, Christ's baptism in the Jordan River by John the Baptist is commemorated. The third day is devoted to the Feast of St. Michael, the archangel, one of Ethiopia's most popular saints. Since October and the end of the rains, the country has been drying up steadily. The sun blazes down from a clear blue sky and the Festival of Timkat always takes place in glorious weather. Enormous effort is put into the occasion. Tej and tella (Ethiopian mead and beer) are brewed, special bread is baked, and the fat-tailed African sheep are fattened for slaughter.Gifts are prepared for the children and new clothes purchased or old mended and laundered.
Everyone men, women, and children appear resplendent for the three-day celebration. Dressed in the dazzling white of the traditional dress, the locals provide a dramatic contrast to the jewel colors of the ceremonial velvets and satins of the priests' robes and sequined velvet umbrellas.
On the eve of the 18 January, Ketera, the priests remove the tabots from each church and bless the water of the pool or river where the next days celebration will take place. It is the tabot (symbolizing the Ark of the Covenant containing the Ten Commandments) rather than the church building which is consecrated, and it is accorded extreme reverence. Not to be desecrated by the gaze of the layman, the engraved wooden or stone slab is carried under layers of rich cloth. In Addis Ababa, many churches bring their tabots to Jan Meda (the horse racing course of imperial day) accompanied by priests bearing prayer sticks and sistra, the ringing of bells and blowing of trumpets, and swinging bronze censors from which wisps of incense smoke escape into the evening air. The tabots rest in their special tent in the meadow, each hoisting a proud banner depicting the church's saint in front.
The priests pray throughout the long cold night and mass is performed around 2:00 a.m. Huge crowds of people camp out, eating and drinking by the light of flickering fires and torches. Towards dawn the patriarch dips a golden cross and extinguishes a burning consecrated candle in the altar. Then he sprinkles water on the assembled congregation in commemoration of Christ's baptism. Many of the more fervent leap fully dressed into the water to renew their vows.
Following the baptism the tabots start back to their respective churches, while feasting, singing and dancing continue at Jan Meda. The procession winds through town again as the horsemen cavort alongside, their mounts handsomely decorated with red tassels, embroidered saddlecloths, and silver bridles. The elders march solemnly, accompanied by singing leaping priests and young men, while the beating of staffs and prayer sticks recalls the ancient rites of the Old Testament.