Polls opened in Colombia at 8 a.m. Sunday in a historic vote to decide the fate of the peace agreement signed between the government of President Juan Manuel Santos and the Revolutionary Armed Forces of Colombia (FARC).

That deal, four years in the making, stands to end more than five decades of conflict between Colombia’s armed forces and its largest guerrilla group.

First, Colombians must approve the agreement in a plebiscite.

“Yes” or “No” to peace deal

The choices are simple: “yes” to uphold the deal or “no” to strike it down. But for the millions of Colombians who have been affected by years of fighting, the impact of Sunday’s vote is significant.

In the weeks since a final deal was reached in Havana and the plebiscite date was announced, the campaigns for “sí” and “no” have become decidedly political. Most prominent is the clash between ex-president Alvaro Uribe, who supports the “no” vote, and sitting President Juan Manuel Santos, whose administration negotiated the accords.

Nonetheless, the most recent polls show the “yes” voters have a significant lead.

Weather delays and a rainy morning

It is not an ideal day to head to the polls in much of Colombia, however.

In parts of Colombia’s Caribbean, heavy rains spiraling off of Hurricane Matthew delayed the opening of some voting locations. Dreary weather affected other parts of the country as well, including the capital Bogotá.

The national Attorney General’s office announced early Sunday morning that aside from weather delays, voting was proceeding with “total normality” across Colombia.

By 9 a.m. many Colombians living abroad had already cast their votes. Polling places in Germany, Belgium, South Africa, France and Egypt, among others, closed early Sunday morning in Colombian time.

Several public officials announced their votes on social media, including Bogotá Mayor Enrique Peñalosa, who voted “yes” and former President Álvaro Uribe Vélez, who voted “no.”

A nationwide alcohol ban “Ley seca” has been in effect since Saturday and ends Monday morning. Sunday’s bicycle Ciclovía in Bogotá has been cancelled in order to allow voters to reach their voting stations.

According to a poll released late September by Datexco, the “yes” vote should lead “no” by a margin of 55% to 37%. The final vote count is expected by 9 pm.

At least 13 percent of eligible voters — or 4,536,993 Colombians — must approve the peace deal in order for it to pass.