Alalee, you live in a state that has four distinct growing zones....5, 6, 7, & 8.
You say you live in part of the state that is in the eastern zone....so must be either 5 or 6.
Plants...and grass is nothing but a lot of plants, grow according to the soil conditions and a time of year that its temperature decides on what can grow in it, and how fast.

Mind you I said temperature....IN IT....so we speak of soil temperature...not air temperature.
If you lived in the far west of Washington, then your growing time is far longer.
You have to assume the soil in the eastern zone is now at a point that has fast cooled off as far as new growth.
It is true that perennials,s shrubs and trees, and yes, lawns, grow well at this time. The reason is there is less competition from other plants...the cool weather encourages root development....not leaf production; so the plant can concentrate to set its roots before winter freeze.

However, grass grows well that is already developed....seed takes time to germinate. Depending on the type of seed you are using, its a general rule that grass seed needs time to germinate and develop strong enough to withstand the coming freeze. Its now almost October...a frost may have already visited you...if not, it will pretty soon.
You can see if you plant seed now, chances are it wont germinate in time.

You could take a chance and maybe, if the weather co-operates, the soil temperature will stay high enough to develop the seed. There's also a chance it wont.
Sod is different....you can lay sod well into November and expect it to set root.

What measures you take to rid your lawn of the weeds can decide too whether you can plant seed. There would be no way to spray a herbicide to kill weeds if you plan on spreading seed any time soon.

Crabgrass is an annual....it will die when the first hard frost comes. Its the seeds that it throws out now that returns in the spring/summer.
Its too late to put down a pre-emergent---which kills crabgrass seeds--(about 80 - 90%) --think to do that next June/July. Your local full service nursery guy can best advise when's the proper time for your area.

You could spray a broadleaf weed killer now---it wont harm your natural grass--only weeds and maybe get rid of what weeds it can react on. Still, the weeds must be got rid of.
The best way to lessen the effects of weeds is to grow a strong turf grass and leave it high...3" - 3 1.2" which will, over time, provide shade to the soil to stop the weeds from germinating.

Then there's the tried-and- true method....getting down on all fours and digging out the weeds................root and all.
It does no good to just remove the flower head of a dandelion...all you you've done is made it stronger to come back better than it was.
Clover can be killed with a herbicide.

Spot spray the weed directly if its not possible to do an over the area spray.
Roundup....a glyphosate, will kill all green it touches including plants and small shrubs.
It has the advantage of being able to be re-planted soon, within a couple weeks....but time is running out for this season.

The end-all is to try to grow the best lawn you can by letting the grass grow high and shade out the weed seed

Good advice above.

I just want to mention that pre-emergents don't actually kill seeds. They just prevent them from germinating. Crabgrass will germinate when the soil hits about 60 degrees, so you need to apply a pre-emergent in the early spring. By June, it will be too late.

Thank you so much for the information

Too bad you didn't write back in August, because that was the time for you to jump on this. Spring seeding might be the very reason you have all the weeds. Spring seeded grass does not have time to develop roots which will withstand summer heat. Also the very act of watering every day causes all the weed seeds to germinate. If you did that this time of year, the summer weeds are not germinating now, and the grass would have time to harden up. All in all, fall is the time to seed new grass.

To kill your clover you will need Weed-N-Feed Clover, Chickweed, and Oxalis killer. Don't bother unless those words are in big black letters on the bottle. You will have to keep after the clover. It drops tons of seed.

If you already have a Kentucky bluegrass lawn, you might not have to seed or anything. Just proper watering, mowing, and fertilizer will be the best for it. This time of year you should be watering no more than once every month. As the temps warm up in the spring you can move to every 3 weeks, 2 weeks, and every week if you ever see a week of temps in the 90s. Water a full inch every time you water.

The reason you have so many weeds this year is you probably tried to compensate for the heat by watering every day or so. That's the wrong approach. Instead water more deeply (longer) in response to high temps.