Photo: JERRYE AND ROY KLOTZ MD · CC BY-SA 3.0Precipitation in Spearfish trails that of 87% of U.S. towns: 25 inches a year
In January the night’s low is typically 15°. May is the wettest month here, with about 5.0 times the rain of January. Winter nights are cold: in January they are colder than in 84% of U.S. towns. If you like long walks, May, June, August and September offer highs of 66–84°.
A year in Spearfish at a glance
Each month’s typical high and low, and what it brings.
What stands out about Spearfish’s climate
Compared with towns across the U.S., with Spearfish’s place in South Dakota beside it.
What a year in Spearfish 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, 2.8 miles from the town’s center, 200 ft lower.
The 2023 USDA map puts Spearfish’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −14°. 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 71 inches of snow a winter
Snow, measured at Spearfish, SD, falls mostly in December. 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 93 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Spearfish
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 Spearfish’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, August and September. 26 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Spearfish from natural hazards, river flooding is the largest share (51%); heat waves, cold waves, winter storms and ice storms together are 16%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Spearfish and similar climates
TownRatings has no climate map of the towns around Spearfish yet.
Climates most like Spearfish’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 |
|---|---|---|---|---|
| Spearfish, SD | 15° | 86° | 25" | 71" |
| Air Force Academy, CO | 14° | 84° | 21" | 55" |
| Flagstaff, AZ | 16° | 84° | 18" | 90" |
| Ranchettes, WY | 16° | 85° | 16" | 65" |
| Alpine, UT | 21° | 88° | 24" | 74" |
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 Spearfish averaged 1.0° warmer than the 1900s. The biggest change is in January (+3.1°).
A smaller shift than in 77% 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 Spearfish compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Spearfish’s place among South Dakota’s.
Spearfish weather by month
Highs, lows and precipitation from NOAA’s grid at Spearfish’s center; snow, wet days and snow on the ground from Spearfish, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 37° | 15° | 0.9" | 8.2" | 7 | 17 | 17° – 37° |
| February | 38° | 16° | 1.1" | 12.7" | 7 | 13 | 8° – 36° |
| March | 48° | 24° | 1.5" | 12.0" | 6 | 10 | 24° – 46° |
| April | 56° | 32° | 2.7" | 8.5" | 9 | 4 | 37° – 50° |
| May | 66° | 41° | 4.3" | 2.3" | 12 | 1 | 46° – 59° |
| June | 77° | 51° | 3.7" | 0.0" | 12 | 0 | 58° – 70° |
| July | 86° | 57° | 2.5" | 0.0" | 9 | 0 | 63° – 77° |
| August | 84° | 55° | 2.0" | 0.0" | 7 | 0 | 64° – 75° |
| September | 74° | 46° | 1.7" | 0.1" | 6 | 0 | 54° – 66° |
| October | 59° | 34° | 2.3" | 5.5" | 7 | 2 | 37° – 52° |
| November | 47° | 24° | 1.1" | 6.3" | 5 | 6 | 25° – 45° |
| December | 38° | 16° | 0.9" | 14.9" | 5 | 16 | 18° – 34° |
| Year | 59° | 34° | 24.5" | 70.5" | 93 | 69 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 8° to 36°. August is the most reliable, staying within 11°.
Where Spearfish’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 Spearfish’s center.
- Snow: Spearfish, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Spearfish, SD, 2.8 miles from the town’s center, 200 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 Spearfish’s climate
What is the weather like in Spearfish?
A typical July afternoon reaches 86°, a January night drops to 15°, and about 71 inches of snow falls in a normal winter. Colder January nights than 84% of U.S. towns; hotter July afternoons than 52% of U.S. towns.
How cold does it get in Spearfish 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 Spearfish get?
About 71 inches in a normal winter at Spearfish, SD, most of it in December, with snow on the ground about 69 days a year.
How hot does it get in Spearfish?
July, with a typical high of 86° 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 Spearfish?
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 Spearfish in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −14°.
What is the best time of year to visit Spearfish?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Spearfish getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 77% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Spearfish.
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.