Temperature Update - June 2018, GISTEMP

The NASA and Goddard Institute for Space Studies GISTEMP anomaly for June 2018 is 0.77°C above the 1951 - 1980 average. This is the coolest monthly anomaly of the year, slightly cooler than January's 0.78°C. This is more an indication of how warm the year has been so far. June is the equal third warmest June on record, equal with June 1998 and 0.03 cooler than the record June of 2015.

Temperatures remain very close to the trend since 1970, of 1.81°C / century.

Prediction

My prediction for 2018 is 0.825±0.088°C, virtually unchanged from last month's prediction of 0.826±0.101°C. This is also very close to the current average for the first 6 months of 0.828°C.

The probability of 2018 being the 4th warmest, between 2014 and 2015, is now more than 80%. There is only a small chance (~2.5%) of finishing below 2014. It is still plausible (~15%) that it will finish 3rd or 2nd.

GISTEMP

Rank	Year	Anomaly	Probability	Cumulative
1	2016	1	0.02%	0.02%
2	2017	0.9	4.46%	4.48%
3	2015	0.87	10.61%	15.09%
4	2014	0.74	82.25%	97.34%
5	2010	0.7	2.27%	99.62%
6	2005	0.68	0.31%	99.92%
7	2013	0.65	0.07%	99.99%
8	2007	0.64	0.01%	100.00%

Finally, this graph shows how the prediction has changed during the first half of the year, with the red line showing the average predicted value based on each months data, and the grey area showing the 95% interval.

As with other data sets the fact that there has been very little change in the forecast reflects monthly temperatures being very close to those expected by the long term trend (since 1970).

Temperature Update - June 2018, RSS

A brief update on the Remote Sensing System (RSS) satellite global temperature, for June 2018. This has the anomaly for June as 0.465°C above the 1979 - 1998 base period. As with UAH this is similar to April's anomaly and slightly up on May's.

June 2018 was the 7th warmest July in the 40 year RSS data set. The last 6 Junes have been 6 of 8 warmest on record.

The trend for all months over the RSS data set, starting in 1979, is 1.95°C / century, with June continuing the pattern of being slightly below the trend.

The average of the last 12 months remains just above the trend line.

Prediction

My prediction for 2018 continues to drop slightly, at 0.526 ± 0.095°C, compared with last months prediction of 0.530 ± 0.105°C.

It is most likely that 2018 will finish 6th warmest, between 2014 and 2015. The estimated likelihood of this is around 75%, compared with 68% last month. There is only a small chance of it finishing below 6th warmest (around 3.5%), in which case it would most likely finish in 8th place. On the other hand there is a better than 20% chance of finishing above 2015 for 5th or better, with 3rd place still being possible.

Full details of probabilities listed below.

RSS 4.0

Rank	Year	Anomaly	Probability	Cumulative
1	2016	0.76	0.00%	0.00%
2	2017	0.65	0.70%	0.70%
3	2010	0.59	7.47%	8.16%
4	1998	0.58	4.36%	12.53%
5	2015	0.56	9.02%	21.55%
6	2014	0.44	75.01%	96.55%
7	2005	0.44	0.30%	96.85%
8	2003	0.39	2.74%	99.59%
9	2013	0.39	0.15%	99.74%
10	2007	0.39	0.02%	99.76%
12	2006	0.35	0.20%	99.96%
13	2009	0.35	0.01%	99.98%
14	2012	0.32	0.02%	100.00%

The average predicted annual value has been mainly dropping throughout the first 6 months of the year, but only slightly, sown about 0.05°C since the prediction in January. The changes so far are well within the 95% confidence interval.

Temperature Update - June 2018, UAH

Halfway through the year and global temperatures continue to be dull, at least according to The University Of Alabama in Huntsville (UAH) satellite data. Dr Roy Spencer announces that the anomaly for June was 0.21°C above the 1981 - 2010 average. This is the same anomaly as for April and 0.03°C above May, and 0.05°C below January, the month with the highest anomaly. So far has only been 0.08°C difference across the range of all months of 2018. This isn't quite the flattest start to a year in UAH history, 1979 and 2002 both had ranges of 0.07°C over the first 6 months, but it is unusual - the average January to June range is 0.25°C.

June 2018 was the 9th warmest June in the UAH data set.

Anomalies for the month of June - UAH6

This graph also gives the impression that Junes as a whole have become more static. Since 2010 there has been relatively little variation in June temperatures compared with the big year to year swings seen previously. I doubt if much can be read into that, it's just a curious observation.

The monthly anomalies continue to be just below the overall trend line.

Monthly UAH6 Anomalies with 12 Month Moving Average and Trend

My prediction for 2018 remains almost unchanged at 0.244 ± 0.091°C, compared with last month's 0.242 ± 0.103°C.

The actual average for the first 6 months of the year is 0.218°C, so this prediction does assume a slight rise in the second half of the year. This in turn is because temperatures are currently just below the trend and the assumption is that it's more likely that temperatures will return to the trend than away from it. It does not take into account any forecasts such as the expected ENSO value.

There has been very little change in the predicted value so far this year, which shouldn't be surprising given the lake of variation in the reported anomalies.

In terms of ranking, UAH continues to show the least certainty, mainly because there is less of a trend in their data. 6th place has the highest probability, but that is still less than 50%. There is around an 80% chance that 2018 will be between 5th and 7th warmest, but with a reasonable possibility it will finish below 7th, possibly as low as 11th. It is unlikely to finish above 5th place.

UAH 6.0

Rank	Year	Anomaly	Probability	Cumulative
1	2016	0.51	0.00%	0.00%
2	1998	0.48	0.00%	0.00%
3	2017	0.38	0.28%	0.28%
4	2010	0.34	2.00%	2.28%
5	2015	0.27	27.08%	29.36%
6	2002	0.22	43.16%	72.52%
7	2005	0.2	11.14%	83.66%
8	2003	0.19	5.78%	89.44%
9	2014	0.18	2.37%	91.81%
10	2007	0.16	4.82%	96.63%
11	2013	0.14	2.20%	98.83%
12	2001	0.12	0.81%	99.64%
13	2006	0.11	0.05%	99.69%
14	2009	0.1	0.21%	99.90%
15	2004	0.08	0.06%	99.95%
16	1995	0.07	0.02%	99.98%
17	2012	0.06	0.01%	99.99%
18	1987	0.05	0.01%	99.99%
19	1988	0.04	0.00%	100.00%