Global temperatures and rain patterns are affected by a climate phenomenon known as El Niño/La Niña.
Simon King explains what it is and what it could mean for our weather.
The Earth's climate is further out of balance than at any time in recorded history, the UN's weather agency says.
The last three years were Earth's hottest on record, as humanity's carbon emissions continue to heat the planet.
The warning comes as cuts to American research raise fears over the ability to track and prepare for them.
January was expected to be cooler than the same month last year, but was 0.1C warmer, which experts are struggling to explain.
The record rise is incompatible with keeping global warming to 1.5C according to the Met Office.
Last year was the world's warmest on record, bringing temperatures above a politically symbolic milestone.
It is also set to be the world's first breach of 1.5C of warming across an entire calendar year.
