Boise didn't break a record for the number of 100º days in 2021, but we came really, really close. Those of us who couldn't wait for things to cool off are finally getting our wish, but didn't expect it to happen so drastically, so quickly!
It's hard to believe that it this time last week, temperatures were still knocking on the door of 90º and now we're asking the question "When can we expect to see measurable snow in Boise?" The question itself isn't silly if you look at the extended forecast. Some local forecasters are predicting lows right at freezing or just below mid-week. Even Kody Wilson of Treasure Valley Weather HQ, our trusted source for everything weather, acknowledges that the timing of the precipitation in this next system could mean the Treasure Valley sees a few flakes before things turn to rain.
So how common or uncommon is October snow in Boise? We dug into some historical data to find out! The National Weather Service shares records of the first and last measurable snowfalls each season in Boise dating back to 1899. In that time, Boise has seen October snowfall 11 times. The earliest October snow, was also the heaviest October snow. In 2008, 1.7 inches fell on October 10. Boise's seen October snows accumulating an inch or more four different years. The most recent October snow, measuring .4 inches happened in 2019.
That said, taking into account all 121 years of data available Boise's average first snowfall happens on November 22. Over the past decade, its happened earlier that seven times. Here's a look at the dates of the first snowfalls from 2010-2020.
- 2010: November 20, .7 inches
- 2011: November 4, .2 inches
- 2012: December 8, .7 inches
- 2013: November 16, 2 inches
- 2014: November 13, 3.3 inches (Two days before the coldest Boise State game on record)
- 2015: November 15, .4 inches
- 2016: December 6, .4 inches (Beginning of Snowpocalypse Winter)
- 2017: December 3, .1 inches
- 2018: December 1, .4 inches
- 2019: October 29, .4 inches
- 2020: November 8, 2.7 inches