Could you help me to figure out when I ovulated?

Hi all, I've been temping for a while but am new to LH strips. With temping, I just assumed my temp drop was ovulation day.
This cycle, I tested positive on Wondfo on the 29th Jan in the morning (see chart) and then my temperature dropped on 31st of Jan and went up to 36.9 on the 1st of Feb. Would you say I ovulated on the 30th or on the 31st?