Answer
About $94^{\circ}C$.
Work Step by Step
The saturated vapor pressure of water equals the external air pressure when it boils. We look in Table 13–3 for the temperature where the saturated vapor pressure of water is 0.80 atm, or $8.1\times10^4 Pa$.
The temperature is somewhere between $90^{\circ}C$ and $100^{\circ}C$. A linear interpolation between those table entries gives $94^{\circ}C$.