What is the current cost of sending a postcard via airmail from Calif. to Europe?

As of my last knowledge update in October 2023, the cost of sending a postcard via airmail from California to Europe typically ranges from $1.40 to $1.50, depending on the specific postal service used and any changes in rates. It's always best to check the latest rates directly from the United States Postal Service (USPS) or your preferred mailing service for the most accurate and up-to-date information.