The record for July is likely to be matched by other agencies in coming days, such as the US National Oceanic and Atmospheric Administration when they release their monthly reports.

If so, it will mean that five of the first seven months of 2015 have been the hottest for their respective months, and make it increasingly likely that this year will eclipse 2014 as the warmest in about 135 years of records.

Preliminary data from US space agency NASA supports Japan's findings that July was the hottest for that month. Here is NASA's chart (via ThinkProgress) showing global warmth anomalies last month:

For Australia, July and winter as a whole have been slightly warmer than average.