It’s a cool start to the final full week of summer in Ottawa, but warmer-than-normal temperatures are expected this week. Environment Canada’s forecast calls for a mix of sun and cloud today. High 18 C. The normal temperatures for this time of year are a high of 19 C and a low of 10 C. It will be clear tonight. Low 6 C. Tuesday will see increasing cloudiness in the morning with a 60 per cent chance of showers late in the morning and in the afternoon. High 20 C. Wednesday will be cloudy. High 24 C. It will be mainly cloudy on Thursday with a 40 per cent chance of showers. High 21 C. The outlook for Friday calls for a mix of sun and cloud. High 19 C. The first day of fall is Tuesday, Sept. 22.