COLORADO -- The first day of August is 'Colorado Day,' a state holiday to celebrate Colorado's existence, and two airlines are battling each other for deals.

Frontier Airlines, which is headquartered in Denver, is offering its best deal of the year Wednesday. Just like every Aug. 1, the airline company is offering discounted flights starting at just $49, and customers can get an extra 5 percent off by using the promo code 'COLORADO' if flying to or from Colorado.

The sale goes through Friday and is good for any flight from Aug. 10 - Dec. 19.

Southwest Airlines is also having Colorado Day sales for customers looking to travel to Denver. The deals are good on Tuesdays and Wednesdays from Sept. 7 - Nov. 12 and start at just $48.

The deals are only good Wednesday.

All 42 state parks will be offering free admission on Monday, just as they do on the first Monday of August every year.

All city government offices are closed Wednesday.

On Aug. 1, 1876, president Ulysses S. Grant signed a proclamation admitting Colorado as a state. That was 100 years after the birth of the U.S., which is why Colorado is nicknamed the 'Centennial State.'