The uilleann pipes did indeed cross the Atlantic with the emigration of the second half of the 19th century (if not before), but they seem to have come close to extinction among Irish-Americans in the mid-20th century, just as they did in Ireland. Chief Francis O'Neill presided over quite a circle of pipers in Chicago in the late 19th and early 20th centuries, but I suspect that respectability is what really did the damage, however valid the point about climate.

The Taylor brothers of Philadelphia are credited with the development of the wide-bore 'concert pitch' pipes which, when copied and perhaps further developed by Leo Rowsome and others, became the standard for much of the twentieth century, in Ireland as elsewhere. An attraction of the Taylor design was that it gave much more volume, important for dances and music-halls in pre-amplification days, though many people regret the loss of tone.

Patsy Touhey was one of several professional uilleann pipers in the US. He played at the Chicago world fair in 1904, but also in music halls where he brought the music to non-Irish audiences. His playing was to become quite influential in Ireland both through his 78 rpm recordings and through his influence on Andy Conroy who moved back to Ireland when he retired.

If you ask the same question on Chiff and Fipple, you'll probably get much more knowledgeable replies. The existence of an uilleann pipes forum on that website reflects a thriving uilleann pipes community in North America today, though this would mostly be due to the post-1970s revival.

I'm not even going to get into the uilleann/union argument!