The main objectives are to determine relation between intracranial pressure (ICP) and its amplitude and to ascertain meteorological variables as possible confounding factors. This is a retrospective observational study of a patient with suspicion of normotensive hydrocephalus. The intracranial pressure, the blood pressure, atmospheric pressure and geomagnetic activity were continuously monitored capturing extraordinary sudden and unexpected atmospheric pressure fall. The physiological changes exceptionally observed during sudden weather changes were described by means of statistical parameters. The data from 73 consecutive hourly measurements was eligible for this analysis. It contained 1022 data points corresponding to all recorded parameters, both climate and physiological ones. After initial stable period, the atmospheric pressure started to decrease from 767 mmHg to 746 mmHg. In parallel, the mean ICP ncreased significantly from 4 mmHg to 14 mmHg. Thus, the mean ICP changed inversely during atmospheric pressure drop. Whereas mean intracranial pressure increased by 10 mmHg during atmospheric pressure fall, the intracranial amplitude decreased by 5 mmHg. On timescale of several dozen hours in this study, the short-term periodic diurnal variations of ICP and blood pressure were displayed. The association between diurnal atmospheric pressure oscillation and geomagnetic activity variation was observed. Both intracranial and blood pressure variations differed significantly between day and night. This study shows that increasing ICP is associated with its paradoxically decreasing amplitude under the influence of sudden and unexpected barometric pressure fall. This study suggests that abrupt changes in atmospheric pressure might impact ICP.