The climate of San Antonio is subtropical, with mild winters and very hot, muggy summers.
The city is located in southern Texas, about 200 km (125 mi) away from the Gulf of Mexico.
Winter, from December to February, is mild, but there may be
variations in temperature. Even in the middle of winter, there can be hot days, with highs of 25 °C (77 °F) and more. In other circumstances, it can get cold at night, and the temperature can drop below freezing.
Occasionally, there may be real cold waves, which last a few days, during which the temperature can drop to -10 °C (14 °F) or below. The record is -18 °C (0 °F), set in January 1949. After 1980, the lowest values were -14.5 °C (6 °F) in December 1989 and -13 °C (8.5 °F) in February
2021.
Sometimes the dangerous phenomenon of freezing rain can occur.
Snow in San Antonio is rare. Normally you have to wait a few years between a snowfall with a slight accumulation and another. In December 2017, 5 centimeters (2 inches) of snow fell. In February 2021, snow reached 15 cm (6 in), as it had not happened for decades. The record belongs to January 1985 with 33 cm (13 in).
In the summer, from June to September, the combination of high temperature and
humidity makes the heat very unpleasant. On the hottest days, it can reach and exceed 40 °C (104 °F). The record is 44 °C (111 °F), set in early September 2000.
From time to time, the city can be reached by the remnants of a hurricane, coming from the Gulf of Mexico or the Pacific. In general, hurricanes weaken when they penetrate inland, however, they can still bring abundant rains. The hurricane season runs from June to November, although they are more likely from August
to October, with a peak in September.
The average temperature of the coldest month (January) is of 11.2 °C (52 °F), that of the warmest month (August) is of 29.7 °C (86 °F). Here are the average temperatures.
San Antonio - Average temperatures (1991-2020)
5 | 17.4 | 11.2 | 41 | 63 | 52.2 |
7.3 | 19.7 | 13.5 | 45 | 67 | 56.3 |
11 | 23.2 | 17.1 | 52 | 74 | 62.8 |
14.7 | 26.8 | 20.8 | 58 | 80 | 69.4 |
19.1 | 30.3 | 24.7 | 66 | 87 | 76.5 |
22.6 | 33.6 | 28.1 | 73 | 92 | 82.6 |
23.7 | 34.9 | 29.3 | 75 | 95 | 84.8 |
23.8 | 35.6 | 29.7 | 75 | 96 | 85.5 |
20.9 | 32.3 | 26.6 | 70 | 90 | 79.9 |
15.8 | 27.9 | 21.8 | 60 | 82 | 71.3 |
9.9 | 22.1 | 16 | 50 | 72 | 60.8 |
5.8 | 18.2 | 12 | 42 | 65 | 53.6 |
15 | 26.9 | 20.9 | 59 | 80.4 | 69.5 |
Precipitation amounts to 820 millimeters (32.3 inches) per year: so, it is at an intermediate level. The rainiest seasons are spring and autumn, due to the clash of air masses. San Antonio is just outside the "tornado alley", however tornadoes can occasionally occur in the period April-June (and more rarely in autumn). Here is the average precipitation.
San Antonio - Average precipitation
50 | 2 | 7 |
45 | 1.8 | 7 |
60 | 2.4 | 8 |
60 | 2.4 | 6 |
110 | 4.3 | 8 |
85 | 3.3 | 7 |
60 | 2.4 | 5 |
55 | 2.2 | 5 |
100 | 3.9 | 7 |
95 | 3.7 | 6 |
55 | 2.2 | 6 |
50 | 2 | 7 |
820 | 32.3 | 81 |
On average, there are around 2,630 sunshine hours per year. Here are the average sunshine hours per day.
San Antonio - Sunshine hours
5 | 160 | February6 | 170 | March7 | 215 | April7 | 210 | May7 | 220 | June9 | 275 | July10 | 310 | August9.5 | 295 | September8 | 235 | October7 | 220 | November5.5 | 170 | December5 | 150 | Year7.2 | 2630 |
Best Time
To visit San Antonio, you can choose spring and autumn (in particular, from mid-March to mid-April and from mid-October to mid-November), to avoid the summer heat. In winter, there are long mild periods, but some very cold days cannot be excluded.
Return to the climate of Texas.
San Antonio - Weather by month
Based on the period 1991-2020
In January, the coldest month of the year, the weather in San Antonio is usually mild. The average temperature is of 11.2 °C (52 °F), with a
minimum of 5 °C (41 °F) and a maximum of 17.4 °C (63.3 °F).
Precipitation amounts to 50 mm (2 in), distributed over 7 days.
The day lasts on average 10 hours and 30 minutes.
The average humidity is 63%.
The average wind speed is 12 kph (8 mph).
In February, the weather in San Antonio is usually mild. The average temperature is of 13.5 °C (56 °F), with a minimum of 7.3 °C (45.1 °F) and a maximum of 19.7 °C (67.5 °F).
Precipitation amounts to 45 mm (1.8 in), distributed over 7 days.
The day lasts on average 11 hours and 10 minutes.
The average humidity is 63%.
The average wind speed is 13 kph (8 mph).
In March, the weather in San Antonio is usually very mild. The average temperature is of 17.1 °C (63 °F), with a minimum of 11 °C (51.8 °F) and a maximum of 23.2
°C (73.8 °F).
Precipitation amounts to 60 mm (2.4 in), distributed over 8 days.
The day lasts on average 12 hours and 0 minutes.
The average humidity is 64%.
The average wind speed is 14 kph (9 mph).
In April, the weather in San Antonio is usually warm. The average temperature is of 20.8 °C (69 °F), with a minimum of 14.7 °C (58.4 °F) and a maximum of 26.8 °C (80.3 °F).
Precipitation amounts to 60 mm (2.4 in), distributed over 6 days.
The day lasts on average 12 hours and 55 minutes.
The average humidity is 64%.
The average wind speed is 15 kph (9 mph).
In May, the weather in San Antonio is usually warm to hot. The average temperature is of 24.7 °C (76 °F), with a minimum of 19.1 °C (66.4 °F) and a maximum of 30.3
°C (86.6 °F).
Precipitation amounts to 110 mm (4.3 in), distributed over 8 days.
The day lasts on average 13 hours and 40 minutes.
The average humidity is 68%.
The average wind speed is 16 kph (10 mph).
In June, the weather in San Antonio is usually very hot. The average temperature is of 28.1 °C (83 °F), with a minimum of 22.6 °C (72.7 °F) and a maximum of 33.6 °C (92.4 °F).
Precipitation amounts to 85 mm (3.3 in), distributed over 7 days.
The day lasts on average 14 hours and 0 minutes. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
The average humidity is 66%.
The average wind speed is 15 kph (9 mph).
In July, the weather in San Antonio is usually very hot. The average temperature is of 29.3 °C (85 °F), with a minimum of 23.7 °C (74.7 °F) and a maximum of
34.9 °C (94.9 °F).
Precipitation amounts to 60 mm (2.4 in), distributed over 5 days.
The day lasts on average 13 hours and 50 minutes.
The average humidity is 63%.
The average wind speed is 14 kph (9 mph).
In
August, the hottest month of the year, the weather in San Antonio is usually very hot. The average temperature is of 29.7 °C (85 °F), with a minimum of 23.8 °C (74.9 °F) and a maximum of 35.6 °C (96 °F).
Precipitation amounts to 55 mm (2.2 in), distributed over 5 days.
The day lasts on average 13 hours and 5 minutes.
The average humidity is 60%.
The average wind speed is 13 kph (8 mph).
In September, the weather in San Antonio is usually warm to hot. The average temperature is of 26.6 °C (80 °F), with a minimum of 20.9 °C (69.6 °F) and a
maximum of 32.3 °C (90.1 °F).
Precipitation amounts to 100 mm (3.9 in), distributed over 7 days.
The day lasts on average 12 hours and 20 minutes.
The average humidity is 64%.
The average wind speed is 12 kph (7 mph).
In
October, the weather in San Antonio is usually warm. The average temperature is of 21.8 °C (71 °F), with a minimum of 15.8 °C (60.4 °F) and a maximum of 27.9 °C (82.2 °F).
Precipitation amounts to 95 mm (3.7 in), distributed over 6 days.
The day lasts on average 11 hours and 25 minutes.
The average humidity is 65%.
The average wind speed is 12 kph (8 mph).
In November, the weather in San Antonio is usually very mild. The average temperature is of 16.0 °C (61 °F), with a minimum of 9.9 °C (49.8 °F) and a maximum
of 22.1 °C (71.7 °F).
Precipitation amounts to 55 mm (2.2 in), distributed over 6 days.
The day lasts on average 10 hours and 40 minutes.
The average humidity is 66%.
The average wind speed is 12 kph (7 mph).
In December, the weather in San Antonio is usually mild. The average temperature is of 12.0 °C (54 °F), with a minimum of 5.8 °C (42.4 °F) and a maximum of 18.2 °C (64.7 °F).
Precipitation amounts to 50 mm (2 in), distributed over 7 days.
The day lasts on average 10 hours and 20 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
The average humidity is 64%.
The average wind speed is 12 kph (7 mph).
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