The Panama Canal will cut the number of ships passing through it starting next month due to a lack of rainfall as the El Nino weather pattern takes hold over the region, the canal operator said on Thursday.

The vital waterway that links two oceans and carries about 5% of global maritime trade relies on rainfall to keep ships moving through the passageway.

From September 3, the waterway will allow 34 ships to pass through it, instead of the current 36, the Panama Canal Authority said.

From September 15, the number of ships allowed to pass through it will drop to 32.

That Panama is met with severe drought even though it is one of the wettest nations on Earth is a sign that El Nino has formed in a warmed-up Pacific Ocean. Rainfall between May and August was about 34% below the historical average for the period, the canal operator said.