If you happen to get caught in the rain around town this weekend without an umbrella, don’t be surprised if a perfect stranger hands you a bright yellow one to keep — just because it’s a nice thing to do.

It’s part of a pay-it-forward project that started two years and 1,000 umbrellas ago and already is generating interest from around the world.

At the time Julie Kresen was driving around Squirrel Hill in a downpour when she spotted a very wet girl waiting for a bus.

Her eyes darted back and forth from the poor drenched soul at the bus stop to an umbrella on the floor of her car, and she quickly decided that giving up her umbrella was the right thing to do.

“She was so thankful, and I felt great about it for hours,” said Ms. Kresen of Emsworth. “I just started thinking, ‘Man, I want to give everybody an umbrella.’ “

And with that rainy day, an idea started to bloom.