2007 tC's ue 5w-20, as listed in the owners manual
Whoever did your oil change at Toyota needs to jump off a bridge, because he/she should have known the proper weight oil to use on your vehicle. Take the car back and tell them to do it right. The only real difference between w30 or w20, besides viscosity, is their temperature tolerances.
5w-30 will work perfectly fine in the summer as it has a higher temperature rating as opposed to 5w-20. But, always use the oil recommended in the owners manual. Each manufacturer test their engines extensively and in tight tolerances. So if it says use a specific weight then use it.
2005 OG Flint Mica
Weapon-R Secret Weapon Intake, Custom Painted Valve Cover, Blue LED Parking Lights, 6000K FlowLighting HIDs, Custom Grills, White LED Map Lights, LED Black Light(front dome), Red LED(rear dome), Red LED Trunk Light, White LED License Plate Bulbs, Red Suede Door Panels, Black Suede A-Pillars, Megan Short Shifter, Relocated License Plate on a Custom Bracket, Tinted Tails and 3rd Brake Light, Tinted Turn Signals, 5% Tinted Rear Windows, 10% Tinted Front Windows, WeatherTech Window Visors, Custom Flat Black Eyelids