Since You Asked: Weather numbers tell only part of the story

After our recent cold weather, I've heard more than one person say global warming can't be real "because look at how cold it's been," or words to that effect.

What I'd like to know is this — when it comes to our own local weather, how many record high temperatures (and lows) have been set in recent decades, compared to 50 years ago?

— Dan L., Medford

We won't get into the business of trying to prove anybody's theories here, Dan.

Whatever conclusions we might draw from local data, there does seem to be pretty convincing evidence that the climate is changing in many parts of the world, especially if you follow the work of people who have spent decades in one place watching the changes happen. (See the Dec, 21-28 issue of the New Yorker magazine for a long story about the disappearing ice in Antarctica, told from the point of view of a scientist who has worked in the same place for three decades.)

Just for fun, we looked at the record high temperatures in Medford for each day in July and August (our two hottest months) and the record low temperatures in December and January (our two coldest months) since the National Weather Service started keeping records here, around 1911.

Here's what we found:

For December, 13 of the record-setting low days occurred before 1970, and 18 after 1970, including 11 during the years from 1990 to 2009. For January, 28 of the record-setting low days occurred before 1970, and three after 1970.

So, for December and January combined, 41 of the low records occurred before 1970, and 20 occurred after 1970.

For July, 12 of the record-setting high days occurred before 1970, and 19 after 1970, including nine during the 20 years from 1990 to 2009. For August, 11 of the record-setting high days occurred before 1970, and 20 after 1970, including seven in the 20 years between 1990 and 1999.

For July and August combined, 23 of the high records were recorded before 1970 and 39 after 1970.

This is not a scientific study in any sense. Extremes are just that — extremes. We'll draw no conclusions of our own, and allow you to consider the data.

One interesting aspect of record-making heat and cold is the tendency for records to happen in clusters of two or three or four days in a row, whether it's a heat wave or a cold snap. Fortunately, the extremes never seem to last more than four days — that's why we like living here!

Send questions to "Since You Asked," Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501; by fax to 541-776-4376; or by e-mail to We're sorry, but the volume of questions received prevents us from answering all of them.

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