There will be one more day of cooler-than-normal temperatures in Ottawa, before hot and humid weather conditions return for the weekend. Environment Canada’s forecast calls for a mainly sunny day today. High 25 C. It will be clear tonight. Low 12 C. Friday will see a mix of sun and cloud. High 27 C. Saturday will see mainly sunny conditions. High 28 C. The outlook for Sunday calls for mainly cloudy with a 40 per cent chance of showers. High 28 C. Monday will see a mix of sun and cloud with a 30 per cent chance of showers. High 27 C. The normal temperatures for this time of year are a high of 27 C and a low of 16 C.