Every month since March, I've posted a chart of the progressive year-to-date global average surface temperature, from GISS. This is the update with December included, so it's the final for the 2015 year. The explanation has been included with each update together with what seem to be things to watch. The next article will be in April (to March) or May.
The main article for the 2015 year can be found here.
Worth noting: Hottest December on Record by 0.34 °C
- 2015 is by far the hottest year on record - see my previous article.
- The year to date average up to and including December is 0.87 °C above the 1951-1980 mean.
- December was an average of 1.12 °C above the 1951-1980 mean and is the hottest December on record, beating the previous hottest by a whopping 0.34 °C. The next hottest was December 2014 (0.78 °C).
- June, October, November and December this year were the hottest on record for the respective months.
- The highest anomaly this year is December at 1.12 °C, October was next at 1.06 °C, followed closely by November at 1.05 °C.
- The lowest anomalies this year so far were April at 0.73 °C, and July also 0.73 °C above the 1951-1980 mean.
- Gavin Schmidt and Tom Karl said that this year would have been the hottest even without the El Nino.
- You can read more about the 2015 year on this other article.
Explaining the chart
The chart is a progressive year to date average, or running mean, for all years from 1995 to the present. What that means is for January each year, it just shows the anomaly for January. For February it shows the average of January and February for each year. For March, its the average of the monthly anomaly from January to March.
If you look at December, each year shows the annual average temperature for the full year. For November, each year has the average for the year up to November, not including December. (As before, I've made it extra large because of all the fine detail.)
|Data Source: NASA GISS - GHCN-v3 1880-09/2015 + SST: ERSST v4 1880-09/2015|