Longtime residents of the Mile High City oftentimes have a belief that the weather on Halloween is frightful more often than not. A look at the empirical data shows that while some years have seen scary weather, most times it isn’t too bad.
Denver has been recording snowfall since 1882. In the 131 Halloweens from then until 2012, snow has fallen on October 31 just 22 times, or a mere 17%. That means historically there is less than a 1 in 6 chance of snow on All Hallows' Eve.
Interestingly enough, there are better chances of snow falling on the day before Halloween and the day after. October 30 has recorded snowfall 21% of the time (28 times) and November 1 on 22% of the days (29 times).
Snow depth, measurable snow on the ground in the morning, has been recorded in the Mile High City since 1921. During those 91 years, snow was on the ground on Halloween morning 16% of the time (15 days).
Here again, there was snow on the ground more often on October 30 and November 1 than on Halloween itself. October 30 comes in with snow on the ground 17% of the time (16 times) and November 1 21% of the time (19 times).
However, when you combine the number of times snow was on the ground the day before, the day after or on Halloween itself, you can see where the perception of snowy Halloweens began. Totaling the three yields 50 days or 55% of the years.
Average temperatures on Halloween are actually relatively comfortable. Daytime highs average 51 degrees and lows dip to 31 degrees on average.
The highest temperature on the date was 79 degrees in 1950. The record low temperature for October 31 was recorded in 1991 at 10 degrees.
A few of the more notable Halloweens on record:
- 2004 – The most recent time Denver received snow on Halloween when 1.4 inches was recorded.
- 2002 – A white Halloween and a very cold one! 1.2 inches of snow was recorded and temperatures during prime trick-or-treating time were only in the mid to upper teens. The high temperature that day, 19 degrees, stands as the record low maximum temperature for October 31.
- 1972 – The snowiest Halloween on record. The high temperature that day was only 30 degrees with a low of 15 degrees. Eight inches of snow fell that day followed by an additional 5.8 inches on November 1.