The interannual and decadal variability and trends of summer (June to August) air temperature over the Oltenia Plain area is analyzed for the period 1961 to 2010. The datasets cover monthly temperatures from six meteorological stations. Linear regression and the non-parametric Mann-Kendall test are used to discover any trends present in the datasets. As expected, the most significant trends found for temperature mark increases of up to 0.5°C. From the temporal variations, a dramatic increase in temperature is observed particularly in the last two decades. This enhancement of average temperature is strongly consistent with the results of present studies made in Europe, warming being mainly attributed to an increase in anthropogenic greenhouse gases. From the spatial distribution viewpoint, most stations behave quite similarly, indicating that the increasing trends are more likely linked to large-scale rather than local processes. The analysis of temperature during distinct seasons is quite important as different seasonal warming rates may have important consequences for natural vegetation, agriculture, human health, and energy consumption, amongst others.