Apr 14 2017

Fewer Mild Weather Days

Published by at 7:15 am under Weather & Sky

Mild weather during the Cherry Blossom Festival in D.C., 2006 (photo by Andrew Bossi via Wikimedia Commons)

Mild weather during the Cherry Blossom Festival in Washington, D.C., 2006 (photo by Andrew Bossi via Wikimedia Commons)

Ah, the mild days of spring!  You know the days I’m talking about, the ones that are perfect for birding, gardening, picnics and outdoor weddings.  The not-too-hot, not-too-cold, not-too-wet weather that makes you happy to be outdoors.

Unfortunately Pittsburgh will have fewer of them in the future. That’s what scientists from NOAA and Princeton University found out when they studied how the warming climate will affect our pleasant weather.

The loss has begun already though you may not have noticed it. For the last 35 years (1980-2015) earth’s climate has been converting 1 nice day per year into something unpleasant, mostly in Brazil, Africa and the Middle East.

By the end of the century the change will affect us.  The world will lose 10 mild days out of 74 but the loss won’t be evenly distributed.  The tropics will lose even more mild days while Canada, Maine and the Rockies can look forward to a pleasant future.

Here’s what our future looks like on the map.  Notice how the eastern U.S. is light orange indicating a net loss.

Change in Number of Mild Weather Days by 2090 (map from Van der Wiel/ NOAA/ Princeton)

Map showing the change in the annual number of mild days across the globe comparing 1986-2005 to 2081-2100. Areas of blue have increased in mild days. Areas of brown see a decline. (Van der Wiel/ NOAA/ Princeton)

That map shows the annual change but in fact it will vary by season.  For instance, Pittsburgh will gain some mild days in the fall (maybe 15) but lose more than that in the summer (25 to 50).  June-to-August will be hot!

Changes in the number of mild weather days by season by 2090 (map from Van der Wiel/ NOAA/ Princeton)

Changes in the number of mild weather days by season for 2090 (maps from Van der Wiel/ NOAA/ Princeton)

The full report includes details on mild weather in major cities at: Shifting patterns of mild weather in response to projected radiative forcing.

Now, more than ever, mild weather is a gift.  Enjoy it while you can.

 

(photo by Andrew Bossi via Wikimedia Commons; click on the image to see the original.
Climate map screenshots from Shifting patterns of mild weather in response to projected radiative forcing
)

(*) “Mild weather” is defined as temperatures between 64 and 86 °F, only a trace of rain (less than 0.04 inches) and low humidity (a dewpoint below 68 °F).

One response so far

One Response to “Fewer Mild Weather Days”

  1. Carol turpinon 14 Apr 2017 at 11:08 am

    More “mild days” in the Rockies may sound good on the surface, but it also means less snow days, which means less over-all water in the Rockies, which means more forest fires. So really, everyone loses. ?

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