The heat is building in Adelaide and the city is in for its hottest February weather in three years. Thursday night was Adelaide's hottest night in more than a month, only cooling to 23 degrees in the early hours of Friday morning. It then quickly warmed up, reaching 34 degrees by 1pm, making it the third day in a row it has been so hot. In addition to the heat, locals have been sweating it out with more humid than normal conditions, thanks to moist northeasterly winds. These hot and humid conditions are ideal for storm develop, with a good chance of thundery action this afternoon. The heat is expected to continue until Monday, reaching at least 33 degrees each day. If this happens it will be the first time the city has had six consecutive February days this hot in three years. Sunday and Monday will be the scorchers, as a low pressure trough brings the hottest airmass over the city and temperatures push about 37 degrees. Thankfully the humidity will decrease on these days as the trough causes winds to tend to the northwest. Nights will also be uncomfortably hot, staying above the low-to-mid 20s. The trough will cross Adelaide late on Monday, bringing gradual cooling during the evening and causing temperatures to drop closer to average for a few days.