It doesn't seem right that slushy hail should be pelting down just shy of May, but that's the kind of day it was during our brief visit to Tallinn, Estonia. Just minutes earlier, the sun had peaked through the cloudy skies, raising hope that the unseasonably cold weather would pass, but alas … it was not yet to be. The weather may have dampened our hair and clothing, but it did not lessen the beauty of this well-preserved medieval old town. Tallinn is truly a magical place, and no amount of bad weather can change that.

After having spent the morning exploring the picturesque stone walls, buildings and cobblestone streets of this ancient Baltic city, we arrived at the St. Catherine's Church in old town just minutes after the hail had started to shower upon us. Shivering in the cavernous space (apparently, the authenticity of the venue extended to its lack of a heating system), we could relate to the Estonian saying our guide had taught us that morning: "Summer … it's the best day of the year." And clearly, that day was not today.

Fortunately, we would soon be basking in warmth, not from the sun, but from the joyful sounds of the Estonian band Curly Strings. I have been a fan of this boisterous Estonian folk group since they first exploded onto the local music scene in 2013. Their infectious and lively blend of Estonian folk songs and poetry mixed with American bluegrass and cross-cultural acoustic pop earned them quick acclaim and a sweep of top awards at the annual Estonian Music Awards, a local version of the GRAMMYs.

To have a band of this stature performing for the National Geographic Orion guests was a true coup, and our guide confirmed as much. "They are the most popular band in Estonia right now," she marveled. "If Estonians knew the band was performing today, there would be a line of people begging to get in." But the Curly Strings concert was our little secret, an exclusive event wedged into our tour of the city.

Violinist and lead singer Eeva Talsi was sporting a long overcoat in the chilly space, but she quickly warmed up the hall with her positive energy, brilliant playing and sparkling voice—not to mention her bouncing locks of white-blond curly hair that seemed to emit rays of sunshine into the room. The Curly Strings quartet (which included Taavet Niller on upright bass, Jaan Jaago on guitar, and Villu Talsi on mandolin) demonstrated why they are such a hot item, playing catchy songs with lyrics that we could all sing along to, even though they were in Estonian.

We emerged from the concert to discover that the rain had stopped. While our visit to Tallinn was short and wet, it was a charming, memorable and musical day in Estonia.