Systemic changes in environmental conditions, such as climate, can have a significant impact on both natural and human systems. This paper provides an improved understanding of the spatio-temporal variations in underlying climate processes, and the potential effects climate change may have on Vietnam's agricultural sector. Statistical methods were combined with geostatistical techniques to test the statistical significance of long-term trends in the climatic variables, graphically representing the distribution of climate patterns, identifying variations and trends of changes over time and their likely effects on agricultural production. By using records of monthly precipitation and temperature for a relatively long-term period (1975–2014) over a high density of 112 meteorological stations across the country, robust statistical and visual evidence of climatic change throughout Vietnam are provided. The Mann-Kendall trend test confirms the statistically significant long-term trends of rainfall and temperature in many regions across the country. The visual analysis shows remarkable changes in the spatio-temporal distribution patterns of those variables and most of the ‘hotspot’ areas identified by geostatistical mapping are in areas with confirmed long-term trends. The long-term significant trends are also concentrated in areas with very high proportion of agricultural land, particularly land used for rice production in the Red River and Mekong River deltas. The findings deliver a better understanding of underlying climate processes and impacts across regions of Vietnam and provide a basis to develop effective climate-related policies for agricultural production in response to changing climatic conditions. •We use data from weather stations at high spatial density recorded over a long period.•Robust visual and statistical evidence of climate change across Vietnam is provided.•We identify key rice-growing areas that are affected with pronounced climatic change.•We evaluate the likely effects of the ongoing climatic change on rice production.