The current article investigates the relationships between solar irradiation and other climate variables of interest for viticulture; as well as with climate indexes used worldwide for viticultural zoning. Global solar irradiation was estimated through satellite imagery and, from this, photosynthetically active radiation (PAR) was calculated using a diffuse fraction model. Data were examined for six viticultural regions distributed along the Río de la Plata coastline, in South Uruguay for vintages 2011 to 2014. Results showed that available solar energy decreases from west to east in the coastline. Interannual variability is greater than spatial variability. Significant correlations were found between solar irradiation and reference evapotranspiration (R2=0.80), sunshine... duration (R2=0.71), maximum (R2=0.48) and mean temperature (R2 =0.39). A negative relationship was found for relative humidity (R2= 0.40). Energy accumulation over the growing period showed a similar behaviour to the Adapted Heliothermal Index (R2=0.98), whereas mean daily irradiation for February was negatively correlated with the adapted Dryness Index (R2= 0.53). At the vineyard scale, a relationship between PAR and global solar irradiation of 48.3% was determined. Due to the limitation to the use of solar energy imposed by high temperatures, the amount of energy used by the vineyard represented a 34.3% of the global solar irradiation. Satellite images allowed for an accurate estimation of solar irradiation in locations where no ground observations are available. Moreover, this information can be used for viticultural zoning and for determining interannual variation of environmental conditions and for analyzing their influence on plant development and vintage quality.