People are saying it is the worst drought for years
More than one million Kenyans risk facing hunger because of a prolonged drought, the UN has warned.
The lack of rains has caused crops to fail and cattle-herders are also struggling to keep their animals alive.
The worst affected areas are in the country's semi-arid south-east regions as well as some parts of central Kenya.
The World Food Programme (WFP) has described the crisis as a "very difficult situation" and appealed to donor countries to offer funds.
Currently some 2.5 million people are receiving emergency food aid in the country but the effect of the drought has meant that a further 1.3 million now also need help.
"People are saying it is the worst drought since 2000," said WFP spokeswoman Gabrielle Menezes.
The regions affected normally harvest their crops once a year, planting them in April and collecting in September after the rains. But this year those rains have failed to come.
The Kenyan government was supposed to have built up a sizeable stock of maize but, following allegations of a corruption scandal, it only has enough to last another six weeks, says the BBC's East Africa correspondent, Will Ross.
Many subsistence farmers are reported to be abandoning rural areas - where they rely on aid - and moving into already over-congested slums in the towns and cities.