Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Union Mills experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 26°F in January while summers reach 75°F in July. Annual precipitation totals 38.9 inches. The area receives 41.7 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 41. 70% of days have good air quality. The city sits at an elevation of 747 feet.
Temperature
26°F Jan (-3°C)75°F Jul (24°C)
Annual Average
51.8°F
4% below US avg
January Average
26°F (-3°C)
July Average
75°F (24°C)
Geography
Elevation
747 ft (228 m)
Area
0.6 sq mi (1.6 km²)
Population Density
261/sq mi
Coordinates
41.4953°N, 86.7839°W
Timezone
America/Indiana/Indianapolis
County
LaPorte County County
Nearest Airport
Porter County Regional (VPZ) 12 miles away
Precipitation & Snow
Annual Rainfall38.9"
2% above US avg
Snowfall41.7"
Wettest Month (Jul)4.22"
Driest Month (Feb)2.00"
Air Quality
AQI Median
41.0
Rating
Good
Good Days %
70.2%
Unhealthy Days
2
Natural Hazard Risk
Overall Risk
Relatively Low
Risk Score
78.9 / 100
Social Vulnerability
48.7 / 100
Community Resilience
82.6 / 100
Hazard Breakdown
Tornado
Relatively High
Hurricane
Very Low
Earthquake
Relatively Low
Wildfire
Very Low
Flood
Relatively Moderate
Hail
Relatively Moderate
Strong Wind
Relatively Moderate
Heat Wave
Relatively Low
Winter Weather
Relatively Moderate
Lightning
Relatively Moderate
Ice Storm
Relatively Low
Drought
No Rating
Cold Wave
Relatively High
Landslide
Very Low
Coastal Flood
Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
3 earthquakes (M2.5+) recorded within 150 km since 1990.
Strongest on record: M4.2.
May 2, 2015
5 km S of Galesburg, Michigan
M4.2
139 km
4 km
Nov 4, 2013
1 km SSW of Lyons, Illinois
M3.2
93 km
1 km
Jan 26, 2012
5 km NE of Topeka, Indiana
M3.0
108 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
484 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF4. Total: 120 fatalities, 1,618 injuries.
Date
Rating
Distance
Path
Fatalities
Apr 21, 1967
EF4
89 km
15.0 mi
33
Apr 11, 1965
EF4
50 km
37.0 mi
36
Apr 11, 1965
EF4
60 km
21.2 mi
31
Apr 11, 1965
EF4
91 km
21.6 mi
5
May 27, 2019
EF3
79 km
13.7 mi
0
Jun 5, 2010
EF3
94 km
7.8 mi
0
Oct 18, 2007
EF3
56 km
20.3 mi
0
Oct 24, 2001
EF3
33 km
47.0 mi
1
May 13, 1980
EF3
93 km
21.0 mi
0
Mar 12, 1976
EF3
26 km
12.1 mi
0
Mar 12, 1976
EF3
94 km
38.5 mi
1
Mar 12, 1976
EF3
28 km
12.6 mi
0
Jun 20, 1974
EF3
58 km
4.5 mi
0
Oct 24, 1967
EF3
37 km
0.1 mi
0
Nov 26, 1965
EF3
33 km
1.0 mi
0
Nov 12, 1965
EF3
58 km
4.1 mi
0
Apr 11, 1965
EF3
38 km
33.1 mi
0
Apr 11, 1965
EF3
24 km
35.6 mi
10
Apr 30, 1962
EF3
29 km
36.5 mi
0
Apr 30, 1962
EF3
30 km
0.1 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Tsunami History
1 tsunami recorded within 500 km.
Highest wave on record: 3.0 m (10 ft).
Year
Location
Cause
Max Wave
Deaths
Distance
1954
MICHIGAN CITY, IN (LAKE MICHIGAN)
Avalanche
3.0 m
7
24 km
Source: NOAA/NCEI Historical Tsunami Database.
Wildfire History
4 wildfires (100+ acres) recorded within 100 km.
Largest: UNNAMED (1,602 acres, 2000).
Year
Name
Acres Burned
Distance
2000
UNNAMED
1,602
87 km
1986
OGDEN DUNS
863
38 km
2021
21-INDU TOLLESTON DUNES EAST
594
37 km
2017
17 INDU COWLES DUNES
522
31 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
26°F (-3°C)
2.5 in
Coldest
February
30°F (-1°C)
2.0 in
Driest
March
40°F (4°C)
2.5 in
April
51°F (11°C)
3.5 in
May
62°F (17°C)
3.9 in
June
71°F (22°C)
4.0 in
July
75°F (24°C)
4.2 in
Warmest, Wettest
August
73°F (23°C)
3.7 in
September
66°F (19°C)
3.4 in
October
55°F (13°C)
4.0 in
November
42°F (6°C)
2.8 in
December
32°F (-0°C)
2.5 in
Union Mills has a seasonal temperature swing of 48°F / from 26°F in January to 75°F in July. Total annual precipitation is 38.9 inches, with July being the wettest month (4.2") and February the driest (2.0").