Air is held inside a non-insulated cylinder using a piston (mass $M=25 \: kg$ and area $A=100 \: cm^2$) and stoppers (of negligible area), as shown in the figure. The initial pressure $P_i$ and temperature $T_i$ of air inside the cylinder are $200 \: kPa$ and $400^{\circ}C$, respectively. The ambient pressure $P_{(\infty)}$ and $T_{( \infty )}$ are $100 \:kPa$ and $27^{\circ}C$, respectively. The temperature of the air inside the cylinder ($^{\circ}C$) at which the piston will begin to move is ______ (correct to two decimal places).