Because July is the hottest month of the year, I've seen this July reported as the hottest month ever in recorded history! I asked the question whether August beat July and was told it's too close to call.
The average for the 8 months to the end of August is 1.05 °C, which is 0.25 °C higher than any previous January-to-August period. The previous highest was last year, which with the latest data had an anomaly of 0.8 °C.
There are now 11 in a row of "hottest months" from October 2015 to August 2016 (that is, hottest October, hottest November, etc.). If we could look back over the entire Holocene, it's probably more than 7,000 years since there was a similar run of hottest months on record, that is, not since the Holocene climatic optimum. (It's probably hotter now than it was back then).
Here is a chart of the average of 12 months to August each year. The 12 months to August 2016 averaged 1.03 °C above the 1951-1980 mean and was 0.23 °C hotter than the 12 months to August 2015:
Now no La Niña?
You can see the global mean temperature trend by month in the chart below, for the strongest El Niño years since 1950, which were followed by a La Nina. I've included the 2015/16 period for comparison. NOAA has called off the La Nina watch. The BoM ENSO update is due out later today.
Not counting 2015/16, of the 7 very strong, strong, and strong-to-moderate El Ninos since 1950, there were only 3 that were followed by a La Nina. The chart spans a 3-year period. That is, for the 2015-16 El Niño and subsequent, it goes from January 2015 to December 2017. (For a more detailed explanation see the HW articles: El Niño to La Niña years with more detail here.)
|Figure 3. Global mean surface temperature for strong or moderate/strong El Nino years that were followed by a La Nina. Data source: GISS NASA|
Where was it hot?
Last month it was simply hot almost everywhere. There were cold patches over northern Russia and a few other places. Look at the map though. The orange and red are dazzling, and not in a good way.
|Figure 4. Map showing mean surface temperature, anomalies for August, from the 1951-1980 mean. Source: GISS NASA|
|Figure 5. Map showing mean surface temperature, anomalies for July, from the 1951-1980 mean. Source: GISS NASA|
Year-to-date average surface temperature
The chart below tracks the year to date. Each point on the plot is the average of the year to that month. For 2016, the last point is the average of all months to date including August. This year is tracking well above 2015, partly because of the El Niño. To drop below the average for 2015, the average anomaly for the next four months would need to be less than 0.49 °C:
|Figure 6. Global mean surface temperature, progressive year to date to August 2016. Data source. GISS NASA|
The next four months would have to be the temperatures of 16 years ago...
Given the speculation that this will be another "hottest year," below is a chart showing the average temperature for the 4 months from September to December from 2000 onwards. To be cooler than last year, the average of the next 4 months would need to be less than 0.49 °C. Only one year had the September-to-December average below 0.49 °C, and that was 16 years ago in 2000.
Related HotWhopper articles
- Hottest July on record - global surface temperature with year to date - August 2016
- Hottest June on record - global surface temperature with year to date - July 2016
- El Niño to La Niña years - May 2016 with more detail here
- Hottest May on record with year to date temperature - June 2016
- Seven in a row: April is the hottest April on record, a 7000 year record? - May 2016
- Hottest March on record, tracking El Niño, and a year to date comparison - April 2016
- Hottest February by far at a whopping 1.35 C above the 1951-1980 mean - March 2016
- Hottest January on record, with El Niño years comparison - February 2016