The month of June 1925 was detected as exceptional in the SW interior of Iberia due to the large number of thunderstorms and the significant impacts that caused, with serious losses in human lives and material resources. We analyzed this event from different, complementary perspectives: the reconstruction of the history of the events from newspapers; the study of monthly meteorological variables of the longest series available in Iberia; and the analysis of the meteorological synoptic situation.

We present the earliest records made in San Fernando, very close to Cádiz (SW Spain). Several previous works have already recovered a significant number of meteorological records of interest in these localities. However, more than 40 000 daily meteorological observations recorded at the Royal Observatory of the Spanish Navy (located in San Fernando) were previously unnoticed and remained neither digitized nor studied. We analyze in detail these newly recovered meteorological readings.

An analysis is made of the records made by Spanish observers of a notable aurora on 18 January 1770 in order to study the characteristics of this event. The records indicate that the phenomenon was observed in both continental and insular territories of Spain. In general, observers described the aurora as red in colour, from sunset to midnight. Calculations of the geomagnetic latitudes of the observation locations indicate this aurora was observed over a wide range of abnormally low latitudes.

A record has been found of an "aurora" observed on 27 October 1856 in the Philippines, practically at the magnetic equator. An analysis of this report indicates that it could belong to a "sporadic aurora" because of low magnetic activity at that time. We provide a possible physical mechanism that could explain the appearance of this sporadic, low-latitude aurora, according to the analyses on the observational report and magnetic observations at that time.

This work explores the meteorological conditions of the hydro-geomorphologic event of December 1909 that triggered the highest floods in more than 100 years at the Douro river's mouth and caused important social impacts over the Portuguese and Spanish territories. The study of this extreme event contributes to a comprehensive and systematic synoptic evaluation of the second most deadly hydro-geomorphologic disaster event occurred in Portugal since 1865.