Does Internet Speed Vary by Season?

Bryan Campbell bbc at
Wed Oct 7 15:04:14 UTC 2009

No, I did not read the article . . . But,  . . .

Yes, DSL speed varies by season . . . or rather, temperature.

But, this is really only the case for _aerial_copper_plant.  Buried 
plant is nearly the same temperature year round.

Copper pair resistance changes with temperature.  And, therefore, the 
link speed of DSL will change depending upon the time of the year 
(temperature) and geographic location.

If there is a difference of but a few degrees of temperature year round, 
then no there will be no difference.  But, if you live in the desert 
southwest or even the mid-west where the temperatures can be 70-120 
degrees different between seasons or even 40-70 degrees different 
between night and day . . . you are going to have pronounced differences 
in link speed.

Worst cast, your link speed might vary 10-20%.  The longer the cable 
length from the central office, the more the variance will be.  But, 
this is something that must be measured on a case by case basis.  And, 
since much of the aerial plant has been replaced with buried plant, this 
really isn't much of a problem anymore.


Joe Greco wrote:
> It used to be that we would notice this, except that it had everything to
> do with temperature *and* dampness.  In the '90's, it was still quite
> common for a lot of older outside plant to be really only "voice grade"
> and it wasn't unusual for copper to run all the way back to the CO,
> through a variety of taps and splice points.  Even though Ma Bell would
> typically do a careful job handling their copper, the sheer number of
> potential points of failure meant that it wasn't unusual for water to
> infiltrate and penetrate.  If I recall correctly, the worst was usually
> a long, hard cold rain (hey we're in Wisconsin) after which people who
> had been getting solidly high speed modem connects would see a somewhat
> slower speed.
> ... JG

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