The local health unit is warning of extreme cold, while the city is adding more beds in shelters, in preparation for a cold snap expected to hit the region. Environment Canada is forecasting temperatures as low as -18 C Friday, or -27 with the wind chill. Overnight, that could drop to -32 with the wind chill. That’s prompted the Windsor Essex County Health Unit to issue a cold weather warning, triggered when temperatures below -15 C without the wind chill are expected.