Metservice forecaster Sarah Hadden said the forecast in the area for the next 12 hours was for fine conditions but with a strong northeasterly building overnight before a southerly brought rain tomorrow afternoon.
Up to 30 lighting strikes were recorded in the area between 5.30pm and 6.30pm.
Fire and Emergency New Zealand spokeswoman Jill Higginson earlier said firefighters were called to a scrub fire on Waipiata-Kokonga Rd just after 6pm.
It was thought a passing lightning storm sparked the fire, she said.
Crews from the Ranfurly and Naseby Volunteer Fire Brigades were involved, with tankers from Palmerston, Middlemarch and Wakari.
Waipiata Country Hotel owner Mark Button said smoke could be seen from the Waipiata township but it was on the Kokonga side of the Taieri River.
A thunderstorm passed through the area about 6pm and Button thought it had sparked two separate fires.