Re-Investigating Ireland's Maximum Air Temperature Record—Kilkenny Castle, 26 June 1887

Abstract

In this study, data rescue and analysis of available station archives from the late 19th and the early 20th century were carried out to re-investigate Ireland's maximum air temperature record of 33.3°C at Kilkenny Castle on 26 June 1887. In addition to analysing this data in detail, we also conducted a comprehensive investigation of newspaper archives and meteorological documents published at the time of the record. The year 1887—and the month of June in particular—was exceptional in Ireland, with unprecedented drought and heat conditions across the island. Many places saw high temperatures during this period, with several stations recording temperatures in excess of 30°C. We also investigated inspectors' reports and station metadata for Kilkenny Castle, which lend support to the record temperature. A thorough analysis of the rescued data showed that for some measures (such as the temperature spread across the island on the day of the record), the data support the record temperature; but for some other measures (such as the monthly mean of maximum temperatures), the difference between Kilkenny and the neighbouring stations appears to be anomalous. Following a careful consideration of all of the evidence from both the metadata and the data analysis, our recommendation is that the long-standing record maximum air temperature value of 33.3°C for Kilkenny Castle on 26 June 1887 should continue to stand, but with some reservations noted.