The paper provides new evidence of the effect of temperature and precipitation on
crop profit of farmers applying different farming systems across different seasons as
well as geographical regions in Vietnam for the period 2004–2016. The result finds
that the effect of fluctuation in temperature and rainfall on the crop profit of farmers
is not uniform across the three regions (North, Central and South) and also consider￾able variation across rain-fed and irrigated farms. For the rain-fed farming system,
(i) rainfall in the dry season has a nonlinearly (T) association with the profit, but
rainfall in the rainy season has no effect, and (ii) dry season temperature and rainy
season temperature have, respectively, T-shaped and U-shaped relationship with the
profit. For the irrigated farming systems, the temperatures in the dry season and
rainy season have a U-shaped relationship with the profit. The findings show that the
irrigated farming systems have been effective in the long term in the face of
climate change. Therefore, in preparation for adaptation to climate change, the
Vietnamese agricultural sector needs a complete irrigation system at both farm and
regional levels.