Historically heavy rainfall in Los Angeles has delayed the highly anticipated, $2.6 billion stadium in Inglewood, California, by a year.

The new facility, to be shared by the Rams and Chargers, will now open in 2020 instead of 2019, the teams said Thursday. In the meantime, the Rams will play at Los Angeles Memorial Coliseum for an additional year and the Chargers will have one more season at StubHub Center in Carson, California.

In a conference call with reporters, Rams COO Kevin Demoff expressed disappointment in the delay but stressed: "This is important to get right."

"Stan's vision is unique," Demoff said, referring to Rams owner Stan Kroenke, who visualized and funded the project. "I think it's an unbelievable responsibility for all of us who work on this project to make sure we deliver that for him, for the fans, for Angelenos, for the NFL and for the world when you talk about an event like the 2024 Olympics. It's much more important to get it right than to make sure you hit a certain date."

Dale Koger, senior vice president and managing director for Legends Project Development, said the initial timeline for the new stadium was "very aggressive" and called the new target date "more conventional," leaving more wiggle room for potential delays.

Opening in the summer also allows for non-football events to take place before the start of the season, said Koger, who acts as the construction project manager for the site.

The new stadium was previously approved to host Super Bowl LV in February 2021, but it remains to be seen whether that will continue to be the case. NFL rules stipulate that a team cannot host a Super Bowl at the end of a stadium's inaugural season, but the league confirmed that a waiver can be obtained in order to bypass that.

NFL spokesman Brian McCarthy said, "It's something the ownership would need to consider." Commissioner Roger Goodell previously waived the NFL's rule on minimum temperatures at the Super Bowl so that MetLife Stadium in New Jersey could host Super Bowl XLVIII.

The new home of the Rams and Chargers now isn't expected to open until 2020, a year later than planned. REUTERS/Lucy Nicholson

Two NFL executives estimated to ESPN that the Rams would lose at least $80 million in future revenue by moving into their new stadium in 2020 instead of 2019, including more than $40 million in sponsorship and ticket sales.

"Certainly there will be a revenue hit, and there will be an added-expense hit," Demoff said. "But this is not a decision about economics. This is a decision based on quality and fan experience."

Record-setting rain this winter coincided with the mass excavation period of construction, causing significant delays in which developers basically lost the better part of two months in January and February.

In a statement, Chargers president of business operations A.G. Spanos said: "Our future home will be the best stadium in the NFL and deliver a transformational experience for Chargers fans. If getting it right means pushing back the completion date, then I think the extra year is well worth it. Construction is our family business, so we understand the challenges that come with a project of this magnitude."

The Chargers will be tenants at the new stadium and pay $1 a year in rent.

The new stadium is close to Los Angeles International Airport, but Koger said only weather, and not regulations from the Federal Aviation Administration, delayed the new stadium.

The Rams were planning to roll out a redesign of their uniforms for 2019 to coincide with the opening of the stadium. The organization remains in talks with Nike and the NFL on a potential rollout and is undecided about whether that will take place in 2019 or 2020. Demoff said that decision will be made "in the coming months."

The organization still expects to put personal seat licenses on sale this fall, in conjunction with the Chargers, as originally planned. Per NFL rules, the Rams probably will have to play another international game in 2019 because they will continue to play out of a temporary stadium.

The Coliseum is in the early stages of $270 million renovations that are expected to be completed for the 2019 season. A report Thursday by Sports Business Journal said United Airlines has reached an agreement to buy the naming rights of the Coliseum for more than $70 million over 15 years, making it the richest naming-rights deal in college football.

The new stadium, currently called L.A. Stadium and Entertainment District at Hollywood Park, will seat 70,000 fans and include an adjacent, 6,000-seat performance venue, all of which will be the centerpiece of a site that will take up nearly 300 acres where the Hollywood Park Racetrack used to be.

The venue is expected to include a hotel, office space, retail and housing, and is also in the running to be a venue for the 2024 Summer Olympics if Los Angeles is selected as host.

Developers began working on the site in November. Climate research conducted before construction began allotted for 30 days of wiggle room for rain, but a six-month stretch from October through April produced 120 percent the amount of rain for a typical year in the area. In January, the region was on pace for the fifth-wettest winter in 80 years. At the site, the water was filling up the bottom of a 70-foot hole, causing 12-15-foot puddles and shutting down construction.

The aggressive initial schedule, the surprising amount of rain and the fact that the stadium will be occupied by two teams -- which means it will be used every weekend of the NFL schedule and needs to be ready from the start -- ultimately made pushing the target date back an easy decision. And moving it to the following summer made sense to the two teams.

"Once you get past the season," Demoff said, "and once you realize that you can't open it to begin the season, really your next logical timetable for opening is late spring, early summer, because there are no events that you can put in the building really in the January through April time frame."

The stadium hole is now 90 feet deep and fully excavated, with 6 million cubic yards of dirt removed from the site.

Koger still expects the new stadium to be "transformative to the area."

"And to really put it out there on a rush-rush basis because of the weather just didn't make a lot of sense to anyone," Koger said. "Mr. Kroenke and the Spanos family got together, came to us, we studied it, and it just makes a lot of sense to go with a more conventional schedule."

Information from ESPN's Darren Rovell was used in this report.