Citi details new rewards program, launch date for co-branded Costco Anywhere Visa Card

We now know when exactly Costco is saying goodbye to American Express and hello to Citi and Visa -- plus how the new reward system will work.

American Express has already sent mailers notifying cardholders that their co-branded Costco credit cards will be discontinued this summer.

Now, Citi has launched a web site with information about the Costco Anywhere Visa Card by Citi.

When is the switch?

According to Citi, you can start using your new card on June 20, 2016 (your new Visa card will be mailed in May). This is also the day Costco Warehouses will start accepting any Visa cards.

That means you can keep using your AmEx through June 19, 2016. American Express Costco cards will automatically be canceled and won't work at any stores.

You do NOT need to apply for a new card. In May, Citi will mail a new card directly to you.

How are the rewards?

Costco members can earn:

The card doesn't have an annual fee. You just need to pay your annual Costco membership.

The American Express cards provided 3-percent cash back on gas up to $4,000 per year, 2-percent on restaurants and eligible travel and 1-percent on other purchases.

Sean McQuay, a credit card expert for Nerdwallet, told the Chicago Tribune that makes the Visa card a "no-brainer" for existing members, but also one of the better cash back cards on the market that could be enticing for people who aren't currently Costco shoppers.

McQuay says no card offers better cash back rates on gas, restaurants and travel, but customers who see the biggest chunk of their credit card bill going to groceries may get more cash back with a different card.

"It's safe to say Visa wanted to win this deal a lot," he said.

Will Costco accept all Visa cards?

Yes. But obviously to get the perks mentioned above, you'll need to use the Costco Anywhere card starting June 20.

Citi also notes that the company is not pulling a credit report. But rather transferring your account from AmEx to Citi.

The new card will also serve as your Costco membership card -- just like before.

Costco says you will not lose any rewards earned with the American Express Costco cards up to June 20. Those rewards will move to the new Visa cards, along with any outstanding balances you may have.