Several studies have shown that aggregate stability, saturated hydraulic conductivity ( K s ) and shear strength of soil are important parameters that affect the results of soil erosion models. In most models, the temporal (seasonal) variations of these parameters are not considered so far. Temperature is one of the factors affecting the seasonal variation of these parameters. Consequently, modeling the effect of temperature on these parameters may be useful to improve the modeling of runoff, soil erosion and sedimentation. Therefore, this study was conducted to determine the effect of temperature on soil hydraulic and mechanical properties, and soil erosion. Twenty eight soil samples with different texture, equivalent calcium carbonate (CCE) and organic matter were collected from topsoils in Isfahan and Chaharmahal-va-Bakhtiari provinces. In the first study, the correlation and correspondence between different methods for measuring/estimating aggregate stability and soil strength were examined. The studied soils were clustered based on intrinsic properties (sand, silt, clay, CCE and organic matter). The results showed that different methods and indices [except rill erosion rate (D r ) and shear strength measured with shear vane ( ? s )] similarly predicted the variation of aggregate stability in different soil groups. Therefore, the methods might be used alternatively for soil structural stability determination. The second study was conducted to investigate the effect of temperature on soil structural stability indices and soil erosion. In this study, the shear strength as measured with a fall-cone penetrometer ( ? f ), splash erosion rate (SE), and the modified Emerson water dispersion test (MEWDT) were determined at ambient temperatures of 5, 10, 15, 20, 25 and 30 ?C. The D r and ? s were also measured at ambient temperatures of 5, 15 and 25 ?C. Structural stability indices of high energy moisture characteristic (HEMC) were calculated from the fast wetting data at ambient temperatures of 5, 10, 15 and 30 °C. Also, Counting the Number of water-Drops (CND) for disintegration of an aggregate, which is the standard method in the LISEM model, was measured at two low and high temperatures (i.e., representative of winter weather and laboratory temperature). The results showed that with increasing ambient temperature, aggregate stability indices (SE, MEWDT, HEMC indices and CND) decreased. The D r and ? s had no specific trend with ambient temperature. The results showed that, with increasing temperature to a certain value (depending on the soil type or cluster), ? f decreased and then increased with temperature. The effect of temperature on soil structural stability was explained by three major mechanisms: i) change in volume of entrapped air and its expansion, ii) change in contact angle (wetting coefficient) and hydration rate, and iii) change in pore radius due to changes in Debye length. With increasing temperature, the hydration rate has increased and the solubility of carbonates and air in the soil solution has decreased and, as a result, the soil aggregate stability in water decreased. The third study was carried out to determine the effect of ambient temperature on soil hydraulic properties. In this part, soil hydraulic properties were measured in saturated and unsaturated conditions at ambient temperatures of 5, 10, 15, 25 and 30 ?C. Saturated hydraulic conductivity ( K s ) was measured using the constant-head method on the 28 soil samples in two times. Soil hydraulic properties were measured with a tension infiltrometer on selected 12 soils at the mentioned ambient temperatures. In both experiments, the measurements were also done on a sand sample (size range of 0.1?0.3 mm) as control. The results showed that for the sand sample, the K s measured by the two methods (i.e., constant head at both times and tension infiltrometer) almost linearly increased with temperature. However, in the studied soils, the K s measured by the constant-head method in the first time decreased with increasing temperature up to 15 °C and increased slightly at 20 °C and then again decreased with further increase in temperature. In the second measurement time, the K s continuously decreased with increasing temperature. Keywords Aggregate stability, Fall-cone penetrometer, Splash erosion, Wet sieving, High energy moisture characteristic, Tension infiltrometer, Ambient temperature.