Disclaimer: All of the data displayed here comes from the Japanese Meteorological Agency and this page nor its authors are associated with this organization. For all official information regarding weather and climate in Japan, please visit the JMA website.
Brief note about the data and figures:
The underlying code scrapes the data from the JMA monthly climatology tables. While this data includes flags for inhomogeneity caused by changes in instrumentation, observation methods and/or site location; the code does not account for these and uses all available data.
The code uses the ERSST based ONI index to determine the phase and strength of the ENSO event. From there, it computes the JFM averages of each variable for each ENSO year and bins them by their respective phase and strength.
The figure output and mapping is automated, meaning that some of the snowfall figures present gibberish. This is caused by a small sample of underlying data. For example, the Irozaki station plots with only 2 valid months of snowfall data in its whole record. Please use the snowfall maps with caution as they are most impacted by sample size and data inhomogenity