Sinai, SD

Full City Profile · South Dakota · Lake County County

3.6 /5.0
B+ Good
220 Population 595/sq mi density
$52,188 Median Income $24,065 per capita
$91,500 Home Value $323,488 Zillow
45°F Avg Temperature
B+
Overall
3.6 / 5.0
Good overall score based on economy, affordability, safety and education
B
Economy
3.2 / 5.0
$52,188 median income, 7.6% unemployment
A+
Affordability
5.0 / 5.0
$91,500 home value, /mo rent
C+
Education
2.7 / 5.0
21.3% bachelor's degree or higher
Sinai has a cool climate with an average annual temperature of 45°F (7°C). Winters average 15°F in January while summers reach 72°F in July. Annual precipitation totals 26.2 inches. The area receives 35.8 inches of snow annually.

Temperature

15°F Jan (-10°C) 72°F Jul (22°C)
Annual Average44.7°F
17% below US avg
January Average15°F (-10°C)
July Average72°F (22°C)

Geography

Elevation1,777 ft (542 m)
Area0.4 sq mi (1.0 km²)
Population Density595/sq mi
Coordinates44.2445°N, 97.0440°W
TimezoneAmerica/Chicago
CountyLake County County
Nearest AirportBrookings Regional (BKX)
12 miles away

Precipitation & Snow

Annual Rainfall 26.2"
31% below US avg
Snowfall 35.8"
Wettest Month (Jun) 4.10"
Driest Month (Dec) 0.58"

Air Quality

Natural Hazard Risk

Overall RiskVery Low
Risk Score32.6 / 100
Social Vulnerability25.9 / 100
Community Resilience74.2 / 100

Hazard Breakdown

Tornado Relatively Moderate
Earthquake Very Low
Wildfire Very Low
Flood Very Low
Hail Relatively Low
Strong Wind Relatively Low
Heat Wave Very Low
Winter Weather Relatively Moderate
Lightning Very Low
Ice Storm Relatively Moderate
Drought Relatively Low
Cold Wave Relatively Low
Landslide Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

4 earthquakes (M2.5+) within 150 km since 1990. Strongest: M3.6. Most recent: M2.5 on Jan 16, 2022.

Oct 25, 1990 8 km N of Plankinton, South Dakota M3.6 125 km
Jul 26, 2002 0 km WSW of Huron, South Dakota M3.1 94 km
Jan 4, 2021 5 km N of Tyndall, South Dakota M3.1 149 km
Jan 16, 2022 9 km NE of Plankinton, South Dakota M2.5 121 km
Source: USGS (M2.5+, 1990-2025)

Tornado History

530 tornadoes (EF0+) within 100 km since 1950. Strongest: EF5. Total: 8 fatalities, 298 injuries.

Date Rating Distance Fatalities
Jun 16, 1992 EF5 96 km 1
Jun 24, 2003 EF4 58 km 0
May 30, 1998 EF4 75 km 6
Jun 7, 1993 EF4 45 km 0
Jun 7, 1993 EF4 59 km 0
Jun 16, 1992 EF4 97 km 0
Jul 7, 1955 EF4 72 km 1
May 30, 2022 EF3 64 km 0
Jun 24, 2003 EF3 80 km 0
Jun 7, 1993 EF3 53 km 0
Jun 7, 1993 EF3 28 km 0
Jun 7, 1993 EF3 41 km 0
May 7, 1993 EF3 75 km 0
Jun 16, 1992 EF3 99 km 0
Jun 16, 1992 EF3 15 km 0
Jun 16, 1992 EF3 43 km 0
Apr 20, 1985 EF3 85 km 0
May 12, 1984 EF3 89 km 0
Jul 18, 1983 EF3 74 km 0
Jun 15, 1970 EF3 13 km 0
Source: NOAA SPC (EF0+, 1950-2024)

Monthly Weather

Month Avg Temperature Precipitation Summary
January 15°F (-10°C) 0.8 in Coldest
February 19°F (-7°C) 0.8 in
March 31°F (-0°C) 1.4 in
April 45°F (7°C) 2.6 in
May 58°F (14°C) 4.0 in
June 68°F (20°C) 4.1 in Wettest
July 72°F (22°C) 3.2 in Warmest
August 70°F (21°C) 3.1 in
September 61°F (16°C) 2.6 in
October 47°F (8°C) 2.2 in
November 32°F (0°C) 1.1 in
December 20°F (-7°C) 0.6 in Driest

Sinai has a seasonal temperature swing of 57°F / from 15°F in January to 72°F in July. Total annual precipitation is 26.2 inches, with June being the wettest month (4.1") and December the driest (0.6").

View full weather details →