[Ernest_at_the_Beach]

So how to account for this?

Coldest May in 16 Years; 4th Coldest of last 30 years

And this:

Wow - Snow forecast for Olympics, North Cascades (Global Warming Alert)

[cogitator]

So how to account for this?

Weather and interannual climate variability.

interannual: "between years"

variability: "able or apt to vary : subject to variation or changes"