Boulder Canyon gets about 184 inches of snow a winter, more than all but 29 U.S. towns
July afternoons average 84°. Its yearly precipitation falls short of 87% of U.S. towns. The latest 30-year average runs 1.2° warmer than 1901–2000’s, with March up the most. Tender plants can go out after about May 12; in half of years the first frost comes by October 2.
A year in Boulder Canyon at a glance
Each month’s typical high and low, and what it brings.
What stands out about Boulder Canyon’s climate
Compared with towns across the U.S., with Boulder Canyon’s place in South Dakota beside it.
What a year in Boulder Canyon feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 143 frost-free days a year
In half of years the last 32° night comes by May 12 and the first by October 2. Frost and day counts come from NOAA’s station at Spearfish, SD, 15 miles from the town’s center, 490 ft lower.
The 2023 USDA map puts Boulder Canyon’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −15°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 184 inches of snow a winter
Snow, measured at Lead, SD, is heaviest from February through April, about 28 inches a month. Precipitation (rain plus melted snow) adds up to 25 inches a year; May is the wettest month and January the driest. Rain or snow falls on about 133 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Boulder Canyon
93% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Spearfish, SD.
Living with Boulder Canyon’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
143 frost-free days in zone 5b. The last frost comes by May 12 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 2.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September.
Parks & trails →Of the yearly building losses FEMA expects in Boulder Canyon from natural hazards, river flooding is the largest share (71%); heat waves, cold waves, winter storms and ice storms together are 5%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Boulder Canyon and similar climates
TownRatings has no climate map of the towns around Boulder Canyon yet.
Climates most like Boulder Canyon’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Boulder Canyon, SD | 15° | 84° | 25" | 184" |
| Park City, UT | 18° | 81° | 23" | 153" |
| Steamboat Springs, CO | 6° | 83° | 21" | 185" |
| South Lake Tahoe, CA | 22° | 81° | 19" | 179" |
| Lewistown, MT | 12° | 82° | 18" | 112" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Boulder Canyon averaged 1.2° warmer than the 1900s. The biggest change is in March (+3.5°).
A smaller shift than in 60% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Boulder Canyon compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Boulder Canyon’s place among South Dakota’s.
Boulder Canyon weather by month
Highs, lows and precipitation from NOAA’s grid at Boulder Canyon’s center; snow, wet days and snow on the ground from Lead, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 37° | 15° | 0.8" | 24.8" | 11 | 28 | 17° – 36° |
| February | 38° | 15° | 1.1" | 26.2" | 11 | 23 | 9° – 36° |
| March | 47° | 23° | 1.5" | 27.6" | 11 | 20 | 23° – 46° |
| April | 55° | 31° | 2.8" | 29.0" | 13 | 8 | 36° – 49° |
| May | 65° | 41° | 4.6" | 6.7" | 14 | 1 | 45° – 58° |
| June | 76° | 50° | 3.5" | 0.9" | 13 | 0 | 57° – 70° |
| July | 84° | 57° | 2.6" | 0.0" | 12 | 0 | 62° – 76° |
| August | 82° | 54° | 2.0" | 0.0" | 9 | 0 | 63° – 73° |
| September | 73° | 45° | 1.6" | 1.8" | 8 | 1 | 52° – 65° |
| October | 59° | 33° | 2.2" | 19.3" | 11 | 5 | 37° – 52° |
| November | 46° | 23° | 1.1" | 22.3" | 10 | 14 | 25° – 44° |
| December | 38° | 16° | 0.9" | 25.3" | 10 | 21 | 18° – 34° |
| Year | 58° | 34° | 24.8" | 183.9" | 133 | 120 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 9° to 36°. August is the most reliable, staying within 11°.
Where Boulder Canyon’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Boulder Canyon’s center.
- Snow: Lead, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Spearfish, SD, 15 miles from the town’s center, 490 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Boulder Canyon’s climate
What is the weather like in Boulder Canyon?
A typical July afternoon reaches 84°, a January night drops to 15°, and about 184 inches of snow falls in a normal winter. Colder January nights than 86% of U.S. towns; cooler July afternoons than 63% of U.S. towns.
How cold does it get in Boulder Canyon in winter?
January nights average 15°. About 144 nights a year reach 32° or below and 15 reach 0° or below. In the coldest January of the last 30 years the month averaged 17°.
How much snow does Boulder Canyon get?
About 184 inches in a normal winter at Lead, SD, heaviest from February through April, about 28 inches a month, with snow on the ground about 120 days a year.
How hot does it get in Boulder Canyon?
July, with a typical high of 84° and a low of 57°. About 26 days a year reach 90° and 2 reach 100° (Spearfish, SD).
When is the first and last frost in Boulder Canyon?
In half of years the last spring frost (32°) comes by May 12 and the first fall frost by October 2, about 143 frost-free days, at Spearfish, SD.
What growing zone is Boulder Canyon in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −15°.
What is the best time of year to visit Boulder Canyon?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Boulder Canyon getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 60% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Boulder Canyon.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.