Tuesday, October 20, 2026

Downtown Denver clocks a 96 mph sustained wind that still tops the city's official list

1878 · Denver

On the afternoon of October 20, 1878, wind speeds in downtown Denver averaged 48 mph between 3 and 4 p.m., with a one-minute sustained velocity of 96 mph at both 3:27 and 3:48. It remains the highest sustained wind speed ever recorded in the city.

National Weather Service records list the 1878 reading as the top official sustained wind for Denver. Modern gust lists put a 97 mph tornado-related gust from 2013 at the head of the gust table and the 1878 96 mph right behind it. Either way, 96 sustained in the middle of what was still a young city is a number that makes the current high-wind warnings feel like polite suggestions.

The observation came from the downtown station. There are no surviving photographs of hats in flight or signboards in the street, but the number has been carried forward in every subsequent compilation of Denver extremes. Colorado has since recorded much higher gusts in the foothills and on the plains, but for the official downtown record, October 20, 1878, still holds the title.

If you feel a stiff breeze today and wonder whether the sky is showing off, remember it has done this before, and it did it with a one-minute average that would still close most of the airport.

Sources: Thornton Weather / NWS history · NWS Boulder wind extremes · KDVR summary of Denver wind records

The Senate ratifies the Louisiana Purchase and eastern Colorado joins the map without asking

1803 · Washington / future Colorado

On October 20, 1803, the U.S. Senate ratified the Louisiana Purchase treaty by a vote of 24 to 7. The $15 million deal with France doubled the size of the country and included the portion of present-day Colorado east of the Continental Divide.

The treaty had been signed in Paris on April 30. Livingston and Monroe had been authorized to spend up to $10 million for New Orleans and West Florida; Napoleon offered the whole territory for $15 million and they took it. The Senate approved the treaty six months later.

At the time the land that is now Colorado was still largely unexplored by Europeans. The purchase covered the area east of the Continental Divide. Lands west of the divide came later through the Mexican Cession and other adjustments. The Lewis and Clark expedition was already under way by the time the Senate voted; it would map parts of the new territory but only skirted Colorado's eastern edge.

No one in what would become Denver was consulted. The Cheyenne and Arapaho were already there. The gold rush that would actually people the place was still fifty-five years away. On October 20, 1803, the United States simply acquired the paper claim to a large share of the Front Range and the plains that feed it.

Four cents an acre, give or take. The mountains came free with the paperwork.

Sources: Library of Congress · Colorado Encyclopedia / territorial history · National Park Service boundary history

October 20 has delivered 4.5 inches of snow and an 86-degree high, sometimes within living memory of each other

Denver

On October 20, 1936, downtown Denver recorded 4.5 inches of snow as part of a 5.5-inch total over the 20th–22nd. On October 20, 2023, the high reached 86 °F, the warmest reading ever recorded on the date. The record low is 24 °F (2021).

The 1936 snow fell during a stretch that also produced the heaviest September snow on record earlier in the month. Most of the October total came on the 20th. By contrast, the 2023 high of 86 °F broke a 73-year-old record of 83 °F set in 1950. Average highs for the date sit near 63 °F.

Other notables on or near the date include heavy multi-day snows in 1906 (22.7 inches over five days, with the heaviest falling from the evening of the 20th) and early-season storms in 1990 and 2007 that hit the southern suburbs and the Palmer Divide harder than downtown.

Denver's average first measurable snow falls around October 18–19. Some years the date arrives with jackets; some years it arrives with shorts and an argument about whether it is still fall. The calendar does not choose. It just keeps both options open and lets the Front Range decide.

Sources: Extreme Weather Watch · Thornton Weather history · Thornton Weather 2023 record