Azimio leader Raila Odinga has left Jaramogi Odinga Foundation in Upper Hill ahead of the Saba Saba Day demonstrations.
It is not yet clear whether he is headed to Kamukunji Grounds.
He is accompanied by Murang'a Governor Mwangi wa Iria, National Assembly minority leader Opiyo Wandayi and former Mungiki leader Maina Njenga.
Some youth had braved chilly weather to attend the rally at Kamukunji Grounds.
"The rain will not stop us from holding our maandamano. We must demonstrate against this regime,” said a youth.
The youth danced to various beats to keep warm as they waited for their leaders.