Temperatures - January Summary

Belatedly here's a brief summary of all the reports of global temperatures for January 2019.

I'm trying a different format this year, and only intend to release single reports for all the main data sets at the end of each month, when all the data is in. One major change is that I want to use a consistent base line, so all anomalies are translated into anomalies relative to the years 1981-2010. I'm not promising I will keep this up all year - it might depend on how much I can automate the work.

Observations

All surface data sets have January at around 0.4 - 0.45°C warmer than the 1981-2010 average, with satellite data not too dissimilar. UAH was a bit below 0.4°C and RSS a bit above 0.5°C. In all cases this is up around 0.1°C compared with last January. UAH have 2019 as the 6th warmest January, all other data sets have it as the 4th warmest.

This table summarizes some of the details

January

Dataset	Anomaly	Change from Last Month	Change from Last Year	Trend Since 1979
BEST	0.44	-0.03	0.08	1.88
GISS	0.43	-0.06	0.11	1.71
HADC	0.41	0.08	0.18	1.71
NOAA	0.43	0	0.16	1.64
RSS4	0.52	0.12	0.11	1.98
UAH6	0.37	0.12	0.11	1.28

Hopefully that's not too confusing. It shows each data set, with the anomaly for January in Celsius compared with the 1981 - 2010 base period. It also shows the change of that anomaly compared with the previous month (December 2018) and compared with the same month last year (January 2018). Finally it shows the trend since 1979 in Celsius per century. 1979 is used as a start date for consistency with the satellite data.

Predictions

Too soon to take any predictions seriously, but on the basis of one month the prediction would be for 2019 to essentially the same as January, purely on the basis that January was very close to the long term trend.

This table lists the predicted values in °C compared with the 1981-2010 average, and gives the probability of reaching various milestones. So far on the basis of one months data, it seems probable that 2019 will be warmer than 2018, and for surface data, very likely to be one of the 5 warmest years on record. Satellite data is also likely to be in the top 5, but this is less certain due to the strength of 1998 and 2010 in the satellite data. There is a small chance that 2019 will be the warmest year on record, purely due to the natural uncertainty of the coming months, but realistically this seems unlikely to me unless there is a big El Niño in the coming months.

January - Predictions

Dataset	Prediction	Interval	Top 5	Warmer Than 2018	Record Warmest
BEST	0.45	±0.14	96.6%	72.0%	3.0%
GISS	0.44	±0.14	97.4%	71.7%	3.8%
HADC	0.42	±0.15	95.8%	93.8%	14.5%
NOAA	0.44	±0.14	96.6%	87.7%	13.2%
RSS4	0.50	±0.16	76.1%	92.7%	5.0%
UAH6	0.32	±0.18	70.2%	85.0%	1.7%

Finally here are some of the predictions in graph form.