What does mean temperature mean?

Have the last few weeks in the inland northwest been warmer or cooler than normal?

The answer to this question not only depends on your definition of “normal”, but also what aspect of temperature one refers to.  For those of us with the luxury of being outdoors the last couple weeks, it’s been rather damp, dull and “cooler” than what we generally expect for the first half of October.  The storm track has brought through several rounds of precipitation and limited sunbathing opportunities…

Now, if you are a night owl, or a cold intolerant plant in many parts of the inland northwest, things have been quite a bit different.  Several locales are still waiting for their first freeze of the season, and by and large even places like Missoula that officially have seen their first sub-32F night of the fall are finding that it came a bit late this year.

Many vegetable gardens have stayed up past their bedtime this year, though I have noticed some of my neighbors literally tucking into bed their stunted tomatoes over the last week or so.

Indeed, we had a warm September and a lack of a deep trough and cold air mass thus far into fall.  October 2009 saw record smashing cold that had a number of adverse effects on crops and vegetation (and presumably fauna). However, over the past 50 or so years most areas across the inland NW have seen the last spring freeze earlier in the year, and likewise the last autumn freeze occurring later in the year.

Missoula NWS October temperature

Why mean temperature can be deceiving:

Departure from normal minimum temperature Oct 1-14, 2011


Departure from normal maximum temperature Oct 1-14 2011


This entry was posted in Uncategorized by John Abatzoglou. Bookmark the permalink.

About John Abatzoglou

John is an associate professor of Geography at the University of Idaho. John's interests are centered around climate and weather of the American West and their impacts to people and natural resources of the West. John and his Applied Climate Science Lab at the University of Idaho have published nearly 100 papers and book chapters on climate science, meteorology, and applied climate science connecting climate to water resources, wildfire and agriculture. The research group also develops web-based climate services that connect climate data with decision makers to help improve climate readiness of societies and ecosystems.

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