Understanding how solar and terrestrial radiation fluxes interact with natural surfaces and impact water consumption is of wide interest. In eastern sub-humid Bahia, Brazil, scarce surface water stored in lined ponds is used to drip irrigate Sumatra tobacco plants grown under partial shading. This work aimed at monitoring, over two irrigation seasons (2015 and 2016), the water turbidity, the radiation balance (shortwave – SW and longwave – LW components), and the skin water temperature (Tw) in the center of a large storage pond to better understand the energy balance of the storage pond and its impact on evaporation. Auxiliary data from a collocated weather station were also collected. The water turbidity was very low (around 2.6 NTU on average) due to filtration and reverse osmosis of water prior to storage. The mean daily Tw (26.1°C) was nearly always higher than the mean air temperature Ta (21.8°C) due to near-surface absorption of solar radiation. Incoming (Sg) and net SW (Snet) fluxes decreased by 70% on average with cloud cover while downward LW flux increased by 14% due to increased net atmospheric temperature with the presence of clouds. A mean daily albedo of 0.05 was measured for the type of water stored in the irrigation tanks. The net LW flux (Lnet) was consistently negative (−55.1 W m−2 average). Two approaches are proposed for estimating daily net all-wave radiation Rn. The first is Rn = −27.357 + 0.832⋅Snet (r2 = 0.998 and SEE = 9.66 W m− 2) and the second is Rn = Snet – Lnet(MLR) where Snet = 0.95∙Sg for both approaches and MRL represents a multiple linear regression model (r2 = 0.721 and SEE = 6.87 W m− 2). Both approaches use data that are easily collected from a standard automatic weather station.