Temperature Update - April 2018, HadCRUT

According to the UK Met Office Hadley Centre data set HadCRUT, the global anomaly for April 2018 was 0.629°C above their 1961-1990 base period. This is slightly higher than the previous month, and makes April the warmest, by anomaly, month of the year so far. It is the 7th warmest April in the HadCRUT record starting in 1850.

April anomalies from the HadCRUT4 data set.
Anomalies are in °C compared with the 1961 - 1990 base period.

This continues the general theme of 2018 being close to the trend since 1970.

Monthly anomalies from the HadCRUT4 data set, with a moving 12 month average and trend since 1970. April 2018 is highlighted in red.
Anomalies are in °C compared with the 1961 - 1990 base period.

The average for the first 4 months of the year is 0.58°C. The prediction for 2018, using my simple statistical analysis, is 0.612 ± 0.115°C. This is virtually unchanged from the prediction based on last month's data of 0.615 ± 0.126°C.

HadCRUT4 annual anomalies in blue, and the predicted value for 2018, based on data up to April 2018 in red. The red line represents the 95% confidence interval for the prediction.

As far as annual rankings are concerned the most likely outcome is that 2018 will finish 4th, with over 50% likelihood. There's a roughly 80% likelihood of finishing between 5th and 3rd, but very little chance of finishing 2nd or 1st. The is a reasonable chance that 2018 will finish 6th or lower, in which case it could finish much further down the rankings, owing to the number of years with similar average temperatures.

HadCRUT4 - Ranking Probabilities based on Data to April 2018

Rank	Year	Anomaly	Probability	Cumulative
1	2016	0.8	0.11%	0.11%
2	2015	0.76	0.44%	0.55%
3	2017	0.68	12.24%	12.79%
4	2014	0.58	58.40%	71.19%
5	2010	0.56	10.33%	81.52%
6	2005	0.55	5.80%	87.32%
7	1998	0.54	2.04%	89.37%
8	2013	0.51	5.84%	95.21%
9	2003	0.51	1.09%	96.30%
10	2006	0.51	0.24%	96.53%
11	2009	0.51	0.07%	96.61%
12	2002	0.5	0.84%	97.45%
13	2007	0.49	0.51%	97.96%
14	2012	0.47	1.17%	99.13%
15	2004	0.45	0.56%	99.69%
16	2001	0.44	0.08%	99.77%
17	2011	0.42	0.13%	99.90%
18	2008	0.4	0.08%	99.98%
19	1997	0.39	0.00%	99.98%
20	1995	0.33	0.02%	100.00%

Final Round Up

The other surface data sets show similar patterns to HadCRUT and GISTEMP. NOAA was the 3rd warmest April on record, and has a 67% chance of finishing in 4th place, and is very likely to finish between 6th and 3rd.

BEST was the 4th warmest April on record and has a 66% chance of finishing 4th, but only a small chance, less than 5% of finishing below that. BEST has around a 30% chance of finishing in 2nd or 3rd place.