Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Sullivan City has a warm climate with an average annual temperature of 74°F (24°C). Winters average 58°F in January while summers reach 87°F in July. The area gets 312 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 22.5 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 42. The city sits at an elevation of 210 feet.
Temperature
58°F Jan (14°C)87°F Jul (31°C)
Annual Average
74.4°F
38% above US avg
January Average
58°F (14°C)
July Average
87°F (31°C)
Sunny Days
312 days/yr
Geography
Elevation
210 ft (64 m)
Area
3.6 sq mi (9.3 km²)
Population Density
1,092/sq mi
Coordinates
26.2752°N, 98.5644°W
Timezone
America/Chicago
County
Starr County County
Nearest Airport
Mc Allen International (MFE) 23 miles away
Precipitation & Snow
Annual Rainfall22.5"
41% below US avg
Snowfall0.1"
Wettest Month (Sep)3.74"
Driest Month (Mar)0.55"
Air Quality
AQI Median
42.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively Moderate
Risk Score
84.8 / 100
Social Vulnerability
97.0 / 100
Community Resilience
0.4 / 100
Hazard Breakdown
Tornado
Relatively Low
Hurricane
Relatively Low
Earthquake
Very Low
Wildfire
Relatively Low
Flood
Relatively Low
Hail
Relatively Low
Strong Wind
Very Low
Heat Wave
Relatively Moderate
Winter Weather
Relatively Low
Lightning
Very Low
Ice Storm
Relatively Moderate
Drought
Relatively Moderate
Cold Wave
Very High
Landslide
Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
12 earthquakes (M2.5+) recorded within 150 km since 1990.
Strongest on record: M4.4.
Jun 14, 2009
35 km E of Ciudad General Terán, Mexico
M4.4
134 km
18 km
Mar 18, 2014
18 km E of Pueblo Nuevo, Mexico
M4.1
136 km
1 km
Jan 19, 2014
12 km SSW of China, Mexico
M4.1
105 km
12 km
Dec 22, 2013
19 km NE of Ciudad General Terán, Mexico
M4.0
140 km
37 km
Feb 11, 2014
31 km SSE of China, Mexico
M4.0
110 km
41 km
Mar 4, 2014
27 km SE of Los Ramones, Mexico
M4.0
123 km
5 km
Nov 25, 2013
23 km SE of Los Ramones, Mexico
M4.0
125 km
10 km
Mar 2, 2014
15 km SW of China, Mexico
M4.0
108 km
8 km
Nov 30, 2013
26 km SE of Los Ramones, Mexico
M3.9
124 km
2 km
Mar 5, 2014
18 km SSW of China, Mexico
M3.9
109 km
10 km
Nov 26, 2013
22 km S of China, Mexico
M3.6
109 km
37 km
Aug 30, 2016
11 km N of Los Ramones, Mexico
M3.6
120 km
38 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
10 hurricanes (Category 1+) recorded within 500 km since 1980.
Strongest on record: Category 4.
Year
Name
Category
Max Wind
Closest
2020
Hanna
Category 1
92 mph
67 km
2017
Harvey
Category 4
132 mph
238 km
2010
Alex
Category 2
109 mph
240 km
2008
Dolly
Category 2
98 mph
80 km
2005
Emily
Category 3
127 mph
142 km
2003
Erika
Category 1
75 mph
154 km
1999
Bret
Category 4
144 mph
103 km
1988
Gilbert
Category 4
132 mph
188 km
1983
Barry
Category 1
81 mph
144 km
1980
Allen
Category 4
144 mph
66 km
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
102 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF3. Total: 68 injuries.
Date
Rating
Distance
Path
Fatalities
Mar 15, 1983
EF3
35 km
6.1 mi
0
May 12, 1969
EF3
98 km
0.1 mi
0
May 12, 1969
EF3
88 km
0.1 mi
0
Apr 19, 1965
EF3
53 km
1.5 mi
0
May 5, 1991
EF2
29 km
1.0 mi
0
May 24, 1970
EF2
83 km
25.5 mi
0
May 23, 1970
EF2
99 km
4.5 mi
0
May 23, 1970
EF2
99 km
4.5 mi
0
Apr 26, 1967
EF2
13 km
40.2 mi
0
Jun 1, 1962
EF2
81 km
1.0 mi
0
Sep 7, 1956
EF2
99 km
0.1 mi
0
Jan 26, 1950
EF2
81 km
4.7 mi
0
Oct 30, 2015
EF1
90 km
0.7 mi
0
Jun 30, 2011
EF1
41 km
0.4 mi
0
Jul 16, 2007
EF1
34 km
1.0 mi
0
Apr 30, 2003
EF1
13 km
0.3 mi
0
May 21, 2001
EF1
25 km
0.2 mi
0
May 21, 2001
EF1
24 km
0.1 mi
0
Jun 14, 1994
EF1
28 km
0.5 mi
0
Sep 16, 1988
EF1
87 km
0.5 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km.
Largest: BURNS RANCH FIRE (58,395 acres, 2008).
Year
Name
Acres Burned
Distance
2008
BURNS RANCH FIRE
58,395
58 km
2021
KING
9,793
85 km
2022
VIB
7,817
88 km
2017
HOPPER
7,150
91 km
2022
BLANKET
5,823
90 km
2008
ENCINO
3,979
81 km
2021
NORTH JONES
3,541
84 km
2008
UNNAMED
3,389
65 km
2011
KING RANCH
3,075
92 km
2008
JONES RANCH
2,998
68 km
2005
2686
2,979
61 km
2009
HOPPER
2,929
89 km
2021
JONES
2,178
78 km
2010
ENCINITOS RANCH
1,967
59 km
2022
755
1,846
82 km
2011
ENCINITOS
1,748
61 km
2009
STILLMAN
1,466
78 km
2023
ELECTRIC SLIDE
1,410
83 km
2008
SAN RAFAEL RANCH
1,407
61 km
2005
BORREGO
1,392
65 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
58°F (14°C)
1.3 in
Coldest
February
62°F (17°C)
1.0 in
March
70°F (21°C)
0.6 in
Driest
April
75°F (24°C)
1.3 in
May
80°F (27°C)
2.9 in
June
84°F (29°C)
2.8 in
July
87°F (31°C)
1.7 in
Warmest
August
86°F (30°C)
2.3 in
September
83°F (28°C)
3.7 in
Wettest
October
76°F (24°C)
2.3 in
November
67°F (20°C)
1.0 in
December
60°F (16°C)
1.0 in
Sullivan City has a seasonal temperature swing of 29°F / from 58°F in January to 87°F in July. Total annual precipitation is 21.9 inches, with September being the wettest month (3.7") and March the driest (0.6").