Global temperature update

Worldwide, October temperatures were about 0.4 degrees Fahrenheit above 30-year averages, according to satellite data released this afternoon.

While that marked the 20th consecutive month of above-normal readings, it represented a substantial cool-down from September, which worldwide was about 0.7 degrees above.

Temperatures in the Gulf of Alaska were particularly toasty -- around 7 degrees above average during October, said John Christy, at the University of Alabama at Huntsville, one of the keepers of the data.

Overall, October was the eighth warmest among the 35 Octobers in the period of record, and the planet has been warming at the rate of about 0.25 degrees per decade since late 1978, when the satellite tracking began.

We haven’t yet seen the National Climate Data Center October report, but in terms of the global trends, the two databases have tracked fairly closely, although the measurement methods are radically different.

The NCDC readings are based on worldwide surface-measuring;  the NASA and National Oceanic and Atmospheric Administration satellite instruments measure temperatures from the earth’s surface to about 5 miles into the atmosphere.

For example, in the NCDC list, September 2013 ranked as the fourth warmest. On the NASA list, it tied for third.

Locally, officially October finished 3.1 degrees above normal at Philadelphia International Airport, and September was slightly cooler than normal.