Spearfish, United States experiences average highs of 16°C (61°F) and lows of 5°C (41°F) throughout the year. Rainfall is moderate, averaging about 9 rainy days per month. Sunshine is abundant, averaging about 10 hours per day. Average highs have cooled by 0.6°C (1.1°F) across the available records.
Spearfish, United States Weather & Climate 2026
Monthly climate averages for Spearfish, United States. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: Apr–Aug At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
5.1/10
Best: June, July, August, September
UV Index
5
Low
Temperature 16°C / 5°C
Feels Like 13°C / 1°C
Rainy Days 9
Rainfall 49 mm
Sunshine 10 h
Humidity 59%
Wind Speed 20 km/h
Dew Point 2°C
Snow Days 9 days
Frost Days 16 days
Hottest Month
30°C
July
Avg Low18°C
Rain12days
Coldest Month
-7°C
February
Avg High3°C
Rain7days
Driest Month
5days
November
Avg High10°C
Avg Low0°C
Windiest Month
22 km/h
April (Gusts 48)
Worst Time to Visit
Consider avoiding January, February, March, December due to very cold temperatures.
Sun Position
Sunrise 05:11
Daylight 15.5h
Sunset 20:43
Live conditions—
Spearfish on the map · live conditions
Spearfish, United States
- Continent
- Americas
- Country
- United States
- City
- Spearfish
- Population
- 11.3K
- Elevation
- 1,112 m
- Coordinates
- 44.49°, -103.86°
Seasonal Breakdown
Spring
Mar–May
Avg High 14°C
Avg Low 2°C
Rain 11 days/mo
Summer
Jun–Aug
Avg High 29°C
Avg Low 16°C
Rain 11 days/mo
3/3 best months
Autumn
Sep–Nov
Avg High 17°C
Avg Low 6°C
Rain 7 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 3°C
Avg Low -6°C
Rain 7 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 3°C / -6°C . Feb: 3°C / -7°C . Mar: 10°C / -2°C . Apr: 13°C / 1°C . May: 19°C / 8°C . Jun: 27°C / 14°C . Jul: 30°C / 18°C . Aug: 29°C / 17°C . Sep: 26°C / 13°C . Oct: 16°C / 5°C . Nov: 10°C / 0°C . Dec: 4°C / -5°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 20 mm. Feb: 26 mm. Mar: 34 mm. Apr: 80 mm. May: 92 mm. Jun: 66 mm. Jul: 70 mm. Aug: 53 mm. Sep: 44 mm. Oct: 48 mm. Nov: 19 mm. Dec: 30 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 65%. Feb: 61%. Mar: 60%. Apr: 61%. May: 63%. Jun: 57%. Jul: 55%. Aug: 54%. Sep: 54%. Oct: 57%. Nov: 57%. Dec: 62%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 20 km/h . Feb: 20 km/h . Mar: 21 km/h . Apr: 22 km/h . May: 20 km/h . Jun: 19 km/h . Jul: 17 km/h . Aug: 17 km/h . Sep: 18 km/h . Oct: 20 km/h . Nov: 21 km/h . Dec: 21 km/h .
Sunshine
Sunshine
Sunshine: Jan: 7h. Feb: 8h. Mar: 9h. Apr: 10h. May: 11h. Jun: 13h. Jul: 13h. Aug: 12h. Sep: 10h. Oct: 9h. Nov: 7h. Dec: 6h.
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 3. Feb: UV 4. Mar: UV 5. Apr: UV 6. May: UV 7. Jun: UV 8. Jul: UV 8. Aug: UV 7. Sep: UV 6. Oct: UV 4. Nov: UV 3. Dec: UV 2.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 11 days. Feb: 11 days. Mar: 11 days. Apr: 9 days. May: 3 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 6 days. Nov: 8 days. Dec: 11 days.
Climate Trends
Average highs have cooled by 0.6°C (1.1°F) across the available records. Average rainfall is trending wetter by about 12 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 30°C | Jul · 30°C |
| Coldest month | Feb 2025 · -11°C | Feb · -7°C |
| Wettest month | Apr 2025 · 92 mm | May · 92 mm |
| Windiest month | Dec 2025 · 24 km/h | Apr · 22 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Poor April
Poor May
Good June best
Excellent July best
Excellent August best
Excellent September best
Excellent October
Fair November
Poor December
Poor | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 3°C / -6°C | -2°C / -12°C | 6days (20 mm) Good | 6.8h Fair | 65% Muggy | 2.5 Moderate | Poor | View Details |
| February | 3°C / -7°C | -2°C / -13°C | 7days (26 mm) Good | 8h Good | 61% Muggy | 3.5 Moderate | Poor | View Details |
| March | 10°C / -2°C | 6°C / -7°C | 8days (34 mm) Wet | 9.3h Good | 60% Moderate | 4.8 Moderate | Poor | View Details |
| April | 13°C / 1°C | 10°C / -3°C | 11days (80 mm) Wet | 10.1h Excellent | 61% Muggy | 5.7 High | Poor | View Details |
| May | 19°C / 8°C | 18°C / 5°C | 14days (92 mm) Wet | 11.2h Excellent | 63% Muggy | 6.5 High | Good | View Details |
| June best | 27°C / 14°C | 27°C / 13°C | 11days (66 mm) Wet | 12.9h Excellent | 57% Moderate | 7.5 Very High | Excellent | View Details |
| July best | 30°C / 18°C | 31°C / 17°C | 12days (70 mm) Wet | 13.3h Excellent | 55% Moderate | 7.6 Very High | Excellent | View Details |
| August best | 29°C / 17°C | 29°C / 16°C | 9days (53 mm) Wet | 12.2h Excellent | 54% Moderate | 6.9 High | Excellent | View Details |
| September best | 26°C / 13°C | 24°C / 11°C | 8days (44 mm) Wet | 10.3h Excellent | 54% Moderate | 5.8 High | Excellent | View Details |
| October | 16°C / 5°C | 13°C / 1°C | 7days (48 mm) Good | 8.5h Good | 57% Moderate | 4 Moderate | Fair | View Details |
| November | 10°C / 0°C | 5°C / -4°C | 5days (19 mm) Good | 7.4h Good | 57% Moderate | 2.7 Moderate | Poor | View Details |
| December | 4°C / -5°C | -1°C / -10°C | 7days (30 mm) Good | 6.3h Fair | 62% Muggy | 2 Low | Poor | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Spearfish are June, July, August, September, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Spearfish, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Spearfish is July, with average daytime highs of 30°C (87°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Spearfish is February, with average overnight lows of -7°C (19°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Spearfish is May, averaging 92mm of precipitation across 14 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Spearfish runs through May, July, April, June, with the heaviest rainfall in May. Based on 10-year averages for Spearfish.
Spearfish receives approximately 116 sunshine hours per year. The sunniest month is July with around 13 hours. Based on climate data for Spearfish.
The least favorable months to visit Spearfish are January, February, March, December, primarily due to very cold temperatures. For the best conditions, consider June, July, August, September instead.
The annual average UV index in Spearfish is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Spearfish is 59%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes, Spearfish receives snow. Months with snowfall average 9 snow days and 16 cm (6 in) of accumulation, with about 16 frost days during winter.
Average wind speeds in Spearfish are 20 km/h (12 mph). The windiest month is April with peak winds reaching 22 km/h (14 mph) (gusts up to 48 km/h / 30 mph).
Spearfish averages 7 clear-sky days per month with overall cloud cover around 48%. The clearest skies occur in August.
The annual average dew point in Spearfish is 2°C (36°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Spearfish has a Humid Subtropical climate, classified as Cfa under the Köppen system. Temperate climates have mild winters and warm summers, with rainfall spread across the year and four distinct seasons.
The 'feels like' temperature in Spearfish ranges from 1°C (34°F) to 13°C (55°F) on average. Wind chill makes winters feel noticeably colder than the actual temperature — layered clothing is recommended.
Yes, June is a great time to visit Spearfish. It earns a climate score of 8.6/10 with Excellent.
For June in Spearfish, pack Umbrella, Waterproof jacket, Breathable clothing, Sunscreen (SPF 30+), Sun hat. With average highs of 27°C (80°F) and 11 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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