Meteorological winter begins tomorrow. Never mind that it’s felt like winter the last couple of weeks. Nighttime temperatures recently descended into single digits. Snow lingers on the ground, covering bright leaf piles, outlining the shady sides of houses and mountains, melting gently into a still dry earth.

It’s time to relax from garden chores, catch up on indoor work: dig into book and magazine piles, clean the house and think seriously about the past growing season’s successes and failings. Now that the harvest’s in, the compost spread, the tools put away, we gardeners can also play catch up with a changing and challenging climate.

Ouray’s frost-free growing season began May 12, after a morning low barely touched 32 degrees. One hundred and fifty-four days later, Oct. 14, an unusually long growing season ended with the first fall frost, 31 degrees. 2023’s hot, dry and extensive season encouraged borderline crops like pie pumpkins to flourish and ripen, while lettuce pleaded for shade and water.

Until 2006, Ouray’s growing season averaged 121 days – just under four months — from May 29 to Sept. 26. In the last 18, however, the growing season averaged 134 days. It has also varied dramatically — from a 90-day season (just under 3 months) in 2020 to a 161-day season (5+ months) in 2010.

2006 — 111 days

2007 — 108

2008 — 144

2009 — 147

2010 — 161

2011 — 133

2012 — 130

2013 — 114

2014 — 129

2015 — 152

2016 — 143

2017 — 126

2018 — 160

2019 — 128

2020 — 90

2021 — 138

2022 — 145

2023 — 154

Mountain gardeners also face other climate-related challenges. Last week, some unexpected variability showed up in the 2023 U.S. Department of Agriculture Hardiness Zone map update (https://planthardiness. ars.usda.gov) for Ouray. In the 2013 version, the city of Ouray moved from Zone 5B (minimum mean yearly low temperatures -15 to -10) into Zone 6A (minimum mean yearly low temperatures -10 to -5 degrees).

In the 2023 version, based on the years 2013-2022, the city has two different climate zones, 6A and 6B (minimum mean yearly low temperatures -5 to 0 degrees).

Most of the town remains in zone 6A, including the 212 Ninth Ave. National Weather Service weather site on the west side of Main. The warmer 6B zone includes the area east of Main from north of Ninth Avenue south to Fourth Avenue and extends eastward over the Amphitheater Road.

There’s no explanation yet for this rather puzzling change, but I’ve sent a query to the USDA and hope to have an answer soon. Meanwhile, here are the minimum yearly low temperatures recorded at the 212 Ninth Ave. site over the last decade.

2013 — minimum low of 11 below zero

2014 — 1 degree

2015 — 4 below zero

2016 — 2 below zero

2017 — 3 below zero

2018 — 5 degrees

2019 — 5 below zero

2020 — 5 below zero

2021 — 3 degrees

2022 — 3 degrees

Except for the first year, 2013, minimum low temperatures have fallen into the 6B category. That leaves me wondering if the east side of Main and the Amphitheater Road somehow escaped any temperatures below -5º from 2013-2022, and if so, where was this data collected.

My NWS records for 2013-2022 indicate that in six of those 10 years Ouray was cold enough in summer for snow in June: 2013, 2014, 2016, 2017, 2019, 2020. July saw traces of snow in 2013 and 2018. In 2013, 2016 and 2019 there were traces of snow in August.

2013 stands out, though, as an unusually cold, wet year, with snow in all summer months and 25.93 inches of precipitation overall. From January through April, 104.3 inches of snow accumulated, from May through August there were traces of snow each month, and from September through December, 51 inches of snow fell, for a total of 155.3 inches that year. 2013’s mean high temperature was 55.4 degrees, well below the 57.2 degree average from 2006-2020.

NOAA’s most recent forecast for winter 2023-2024 shows a greater than 55% chance of at least a “strong” El Niño persisting January through March 2024 and a 35% chance of it becoming “historically strong” November through January. An “Alert System Status” has been issued for an El Niño “anticipated to continue through the Northern Hemisphere spring (with a 62% chance during April-June 2024.) (“El Niño Southern Oscillation (ENSO) Diagnostic Discussion,” Climate Prediction Center, Nov. 9, 2023.)

The NWS forecast for the end of November / beginning of December shows waves of snow arriving Thursday, Friday and Saturday. Next week, the first full week of December, looks to be warmer and drier.

After a very warm early November, recent snowstorms have cooled the area considerably. As of Tuesday, the average high for the month was 47.9 degrees, the new normal is 46. Lows average 26.2 degrees, normal is 24.4.

Precipitation is only 60% (1.04 inches) of normal, 1.72.

Snow is 59% (11.1 inches) of normal, 18.7.

“In seed time learn, in harvest teach, in winter enjoy.”

—William Blake Karen Risch gardens, records weather for NOAA and CoCo-Rahs, writes and hikes in Ouray. Her Wunderground weather station ID is KCOOURAY3, transmitting weather from latitude N38 1’ 34”, longitude W107 40’21”, Elevation 7,736’. A purpleair. com air quality monitor RISCH operates at the same location.