It’s a sign that summer is nearing an end, with the coldest temperatures in nearly four months expects tonight in Ottawa. Environment Canada’s forecast calls for a mix of sun and cloud today. High 18 C. It will be clear this evening. Low 5 C. The low of 5 C will be the coldest temperature in Ottawa since May 22, when the temperature was 0.6 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 normal temperatures for this time of year are a high of 19 C and a low of 10 C. The first day of fall is Tuesday, Sept. 22.