The pop star shouted out the Swifties Sunday who wouldn't stop dancing during the concert at the Groupama Stadium in Lyon -- despite the immense amount of rain.

Here's what she said ... "So it looks like we have officially had a rain show tonight, this is a rain show for sure. And that is set, that is permanent because it doesn’t matter if it rains again, it really did rain during this show."

Taylor has earned a reputation for battling past bad weather ... notably performing all 3.5 hours of her "Eras" tour last year during "a full-on deluge" in Foxborough, Massachusetts.

It appears Taylor brought a similar dedication to Lyon ... and so did her fans, as she credited them as "absolute champions and heroes for dancing even harder when it started raining."

She added ... "I never could have imagined we would have this much fun on the European tour. It’s just been crazy, you guys and I appreciate you so much."

As we reported ... the singer also took a moment to check in on one attendee, who she saw asking for help amid the bad weather. She shared ... "Yeah we have to take care of these crowds because you’re just the best and you just dance so wildly and sing so loudly."

Taylor also took a moment to commemorate Pride Month during this gig. During her anthem "You Need to Calm Down," TS declared to the crowd, "Happy Pride Month, Lyon," as rainbow lights flashed around her.

Taylor has one more show in Lyon before jetting over to the UK ... which has sparked some controversy. Remember, a homeless nonprofit organization has been railing against the government for moving needy people out of Edinburgh to make way for Swifties.