Both Montreal and Seattle (where I live and where my son lives) have had very cool late spring/early summer. I am wondering if there is any evidence that this is due to that Icelandic volcano.
Volcanic eruptions in the past have been known to disrupt weather patterns worldwide. The
Mt. Pinatubo eruption in the Philippines in 1991 has worldwide repercussions. Every volcanic eruption will cause some sort of weather change, even if just locally. The weather change becomes more expansive based on the size and length of an eruption (or eruption sequence), the material ejected, and the how high into the atmosphere the material is ejected.
Did find this on Wikipedia:
As of 15 April, the eruption was not large enough to have an effect on global temperatures like that of
Mount Pinatubo and other major past volcanic eruptions.   One previous related sequence of eruptions of this volcano, beginning in 1821 is recorded as having lasted for over two years, however no single set of major eruptions is known to have lasted more than ‘several days’. Should the eruption continue for a sufficient length of time at its current intensity, the potential remains for a temporary global cooling effect. By analogy, the Laki eruption has been linked with extreme weather events from severe hailstorms in Great Britain to the Mississippi River freezing at New Orleans.   Sulfate aerosols that reach the stratosphere catalyze the production of chlorine monoxide (ClO), which destroys ozone (O3). In the upper troposphere, the same aerosols become nuclei for cirrus clouds, which increase the Earth’s albedo and thus alter its radiation balance.  Several eruptions during the past century have caused a decline in the average temperature at the Earth’s surface of up to half a degree Celsius for periods of one to three years.
For what it’s worth, the NW was expecting a cooler summer anyway, as a result of El Nino.
Ah, I wondered about that. The range in Montreal today is 54-66 F (12-19 C).