▁pla ins . ▁The ▁Wa ik ato , ▁flow ing ▁through ▁the ▁North ▁Island , ▁is ▁the ▁New ▁Zealand ' s ▁longest ▁river , ▁with ▁a ▁length ▁of ▁. ▁New ▁Zealand ' s ▁rivers ▁feature ▁hundreds ▁of ▁water falls ; ▁the ▁most ▁visited ▁set ▁of ▁water falls ▁are ▁the ▁Hu ka ▁F alls ▁that ▁d rain ▁Lake ▁T au po . ▁ ▁Lake ▁T au po , ▁located ▁near ▁the ▁centre ▁of ▁the ▁North ▁Island , ▁is ▁the ▁largest ▁lake ▁by ▁surface ▁area ▁in ▁the ▁country . ▁It ▁lies ▁in ▁a ▁cal der a ▁created ▁by ▁the ▁O ru an ui ▁er u ption , ▁the ▁largest ▁er u ption ▁in ▁the ▁world ▁in ▁the ▁past ▁ 7 0 , 0 0 0 ▁years . ▁There ▁are ▁ 3 , 8 2 0 ▁la kes ▁with ▁a ▁surface ▁area ▁larger ▁than ▁one ▁hect are . ▁Many ▁la kes ▁have ▁been ▁used ▁as ▁res er voir s ▁for ▁hydro elect ric ▁projects . ▁ ▁Cl imate ▁ ▁The ▁main ▁ge ographic ▁factors ▁that ▁influence ▁New ▁Zealand ' s ▁climate ▁are ▁the ▁temper ate ▁latitude , ▁with ▁prev ail ing ▁w ester ly ▁wind s ; ▁the ▁ocean ic ▁environment ; ▁and ▁the ▁mountains , ▁especially ▁the ▁Southern ▁Al ps . ▁The ▁climate ▁is ▁mostly ▁temper ate ▁with ▁mean ▁temper atures ▁r anging ▁from ▁ ▁in ▁the ▁South ▁Island ▁to ▁ ▁in ▁the ▁North ▁Island . ▁January ▁and ▁February ▁are ▁the ▁warm est ▁months , ▁July ▁the ▁col dest . ▁New ▁Zealand ▁does ▁not ▁have