Low
No protection needed
San Antonio is about to experience a period of extremely hot and sunny weather, the temperatures being likely to reach the upper 90s°F and possibly hitting about 100°F in the coming days. Since people will be spending time outside, the combination of severe heat, strong sunlight and a high UV Index means that it is especially important to take sun protection and stay hydrated.
The weather in San Antonio is currently partly cloudy and the warm conditions will last into the evening. During the day the temperatures are hitting the mid-to-upper 90s°F and overnight the temperatures will be in the 70s°F.
Even though clouds sometimes offer temporary relief from the sun, that doesn't mean the weather will be cool. In the afternoon thunderstorms can also form, especially if hot and humid air stays in place.
If you plan to go to downtown San Antonio, to the River Walk, to the parks or to other outdoor places, you should check the forecast before going out, since the heat can rise rapidly in the afternoon, particularly when there is little shade.
The UV Index in San Antonio may reach very high levels at midday, especially if the skies are mostly sunny, and the greatest UV exposure usually takes place between late morning and early afternoon when the sun is at its highest.
If the UV Index is high then skin not protected by sunscreen will burn rather quickly. Wearing sunscreen with broad-spectrum protection, sunglasses, a hat and light clothing can make being outdoors safer and more comfortable.
Although clouds reduce part of the UV radiation they do not stop all ultraviolet rays, which is why it is useful to check the San Antonio UV Index even on days when it does not look completely sunny.
The forecast indicates that the period will involve hot weather, with temperatures staying in the upper 90s°F and some days possibly reaching 100°F or above.
People who stay outdoors for long periods may face extra risks from this kind of heat, and it is more likely for dehydration and heat exhaustion to occur when exposed for a long time, particularly if the temperature stays high during the night.
It is best to arrange strenuous outdoor activities for the morning or for later in the evening when the temperature is lower. Whenever the afternoon is at its hottest, taking frequent breaks in an air-conditioned or shaded area can make a great difference.
Even though it is very hot, thunderstorms can occur in the afternoon. They may form suddenly and can cause heavy rain, strong winds and frequent lightning. It is typical in San Antonio during the hotter part of the year for there to be a combination of extreme heat and isolated thunderstorms. When you can hear thunder while outside, the best thing to do is to go indoors.
San Antonio has always had hot summers, so it is normal for the city to experience lengthy stretches with temperatures above 90°F. In recent years, extreme heat has come to play a more important role in weather talks throughout Texas.
The fact that the city is situated in South-Central Texas means that it gets a lot of sunshine all over the year. Consequently, UV exposure can still be considerable long after the summer season reaches its peak. Strong UV levels can occur in spring and at the beginning of fall, even though the weather then feels more pleasant.
Weather and exposure to ultraviolet radiation are not always directly linked; a cool but sunny day can still have a high UV Index, and on a very hot day the UV level can at times be lower due to cloud cover. To get a better understanding of the conditions outside, it is necessary to check both the San Antonio weather forecast and UV Index.
For both residents and visitors the key point is simple: the combination of intense heat, strong sunshine and possibly high UV levels in San Antonio means that preparation is necessary. It is important to drink a lot of water, take breaks when it is hot and to use sun protection each time the UV Index is high.