Market also buoyed by short-covering after weekly data from the US Commodity Futures Trading Commission on Friday showed that non-commercial traders slashed their net long position in CBOT corn by about 93,000 contracts, to 14,216 lots in the week to July 12.
Beneficial showers over the weekend that recharged soil moisture offset some of the worries about this week's heat.
However, updated midday forecast models projected hot temperatures in the Corn Belt again next week, revising earlier forecasts that had suggested a cool-down.
Ahead of the US Department of Agriculture's weekly crop progress report due later on Monday, analysts surveyed by Reuters expected the government to rate 75 percent of the US corn crop as good to excellent, down from 76 percent a week earlier.
The USDA reported export inspections of US corn in the latest week at 1,327,509 tonnes, above a range of trade expectations for 1.0 million to 1.3 million tonnes.
Argentine grain truckers started an open-ended strike on Monday over hauling rates, according to a union spokesman.