The Kenya Certificate of Secondary Education (KCSE) examination officially starts Monday with practicals.
Schools are in the meantime expected to close by the end of the week.
The candidates will start the examination with French (oral and braille).
The practicals will end on November 1.
Some of the subjects lined up during the period are German (oral), Arabic (oral), Kenyan Sign Language (practical signing skills) and home science (foods and nutrition).
Kenya Certificate of Primary Education (KCPE) examinations will start on October 30 while rehearsals will take place a day earlier.
KCSE examination theory papers start on November 5 and end on November 29.
Kenya National Examinations Council acting chief executive officer Mercy Karogo asked administrators of practicals to follow the instructions given.
She spoke during a briefing session of those to be involved in the practicals.
The Education Ministry and Knec are leaving nothing to chance, especially after the Meteorological department said rains could pound most parts of the country in the coming two weeks.
In previous years, failure to plan for harsh weather caused problems, especially in flood-prone counties like Tana River.
In 2017, bad weather was blamed for the late start of some papers in parts of northern Kenya.
On Thursday, Education Minister Amina Mohamed briefed the Cabinet on the level of preparedness for the KCPE and KCSE examinations.
The meeting was chaired by President Uhuru Kenyatta.
The Cabinet Secretary said candidates with special needs would be taken care of.
The partially blind will get large print papers while blind candidates will have Braille papers, she added.
Ms Mohamed said Sh4.2 billion has been set aside for the administration of the examinations.
Some 264,446 field officers will be involved in the national tests.
The minister said there will be 180,735 field officers for KCPE and 83,711 for KCSE.
For KCPE, a total of 27,161 centre managers will be deployed. There will be 27,354 supervisors and 65,107 invigilators while security personnel will total 54,322.
Some 6,791 drivers will help distribute the examination materials, the Cabinet Secretary added.
For the KCSE examination, there will be 10,078 centre managers, 10,460 supervisors, 37,978 invigilators, 20,156 security personnel and 5,039 drivers. More boys than girls will sit the national examinations this year, a report presented to the committee showed.
According to the report, a total of 531,548 boys will write the KCPE examination while female candidates are 529,155.
The report adds that 341,089 boys will sit the KCSE examination compared to 323,498 girls.
The 1,060,703 candidates will sit their KCPE tests in 27,161 centres across the country.
The registration of candidates for the 2018 KCPE and KCSE examinations took place between January 15 and March 7.
Ms Mohamed said the examination materials will be dispatched to sub-counties under tight security.
She added that more security personnel will be deployed in areas mapped by the ministry as high risk.
In Narok South Sub-County, some 27 primary schools with an enrolment of 13,476 pupils, including 1,087 candidates, have been affected by clashes.
“In addition, six secondary schools with a total enrolment of 1,183, including 198 KCSE examination candidates, were affected,” the minister added.
In Narok North Sub-County, some 15 schools with an enrolment of 5,791 learners, including 434 candidates, were affected by the tribal clashes.
In Molo and Njoro sub-counties, Nakuru County, some 17 schools were affected by the skirmishes.
According to a report by the Ministry of Education on performance in national examinations, results are usually affected by inadequate English language skills among many candidates.
Other causes of poor performance are misunderstanding questions, poor time management, failure to follow instructions, examination phobia and failure to understand terminology.