I have a 2006 ford explore ,it heats up but it takes about 25 minutes and its 30 degrees out..its gonna get to minus 30 in a month or 2 so do you think mits the thermostat

Yes, replace the thermostat. When driving does it cool back down?

You can change the thermostat, they're cheap enough. I'd also change the coolant to the proper mixture for your area. I've owned four explorers. Down South, where cold is anything 50 degrees or lower, it normally takes about fifteen minutes (at idle) for the engine to reach operating temperature (197 degrees) for the thermostat to open. When it gets to -30, when the engine warms the coolant within the block to 197 degrees the thermostat will open. Keep in mind once it opens it will suck in very cold coolant which must be warmed also. Since the heater operates off the entire cooling system coolant temp, it's going to take a while to get the entire temp of the coolant up to the point where you will be feeling the difference in the air coming out of the vents.

Check your radiator. Carefully feel the front of the radiator from the top down after it gets warmed up. If you have an area that is more cooler than the rest, your radiator is plugged up. Pull it and take it to a shop to have it "rodded" out. Also make sure none of your hoses are collapsing when running. This isn't an old car by comparison so that is doubtful but worth checking.