The early to middle Holocene Humid Period (HHP) was the last time when precession-forced intensification of summer monsoons and northward migration of associated rainfalls led to a greening of today’s arid Saharo-Arabian desert belt. While this wet phase is well confined in N Africa and the S Arabian Peninsula, robust evidence from N Arabia is lacking. Here, we fill this gap with unprecedented annually to sub-decadally resolved proxy data from Tayma, the only known varved lake sediments in N Arabia. Based on stable isotopes, micro-facies analyses and precise varve and radiocarbon dating we distinguish five phases of lake development and prove that the wet phase in N Arabia from 8,800–7,900 years BP is considerably shorter than the commonly defined HHP (11,000–5,500 years BP). Moreover, we find a two century-long peak humidity at Tayma at times when a centennial-scale dry anomaly around 8,200 years BP interrupted the HHP in adjacent regions. This regional disparity is explained by an increased frequency of tropical plumes reaching N Arabia and compensating for the weakened monsoons and/or winter rains. This peak humidity possibly favoured Neolithic migrations into N Arabia indicating very dynamic human response to environmental changes.