We investigated the characteristics of temperature variations under different land covers (paddy field, upland, urban park, and urban residential area) during hot summer (July 15 to August 19, 2005). The temperatures were monitored using data loggers at one hour intervals in study sites. The mean temperature generally increased with the distance from edge of paddy fields, being 1.5℃ higher at a site 170-m far from paddy fields than at a paddy field area at 22 h. The mean daily temperatures in the study period followed the order of paddy field (26.6℃) < upland (27.0℃)< park (27.5℃) < residential area (28.0℃). The paddy field area has shown remarkable cooling effects compared to the residential area: Mean duration of temperature below 25℃ in the paddy field area was longer (8.6 hrs) than in the residential area; The time to fall to below 25℃ in the paddy field area was sooner (22.4 hr) than in the residential area; Mean daily minimum temperature in the paddy field area was much lower (2.4℃) than in the residential area. More research is needed to better clarify the mechanism of cooling effect of a paddy field area by investigating heat balance of a paddy field.