Low
No protection needed
In San Diego, Texas, summer heat becomes a regular part of daily life. Since it is situated in south Texas, the city has long, hot periods, mild winters and considerable variations in rainfall from month to month. The weather conditions observed over the years also account for the fact that the UV Index in San Diego, Texas remains an important consideration for outdoor activities long after the middle of summer.
The peak period of the year is usually the time between late May and September. According to historical climate data, August is generally the hottest month, the average high temperature being about 96°F and the night-time low about 75°F. July and September are also hot, the average high in July being around 96°F and that in September around 91°F.
September is an interesting transitional month since, although the temperatures remain high, rainfall becomes a more significant factor. The average high temperature for September is about 91–92°F and it is also one of the wetter months of the year; the combination of heat, humidity and occasional rain can make the weather seem very different from day to day.
For many years San Diego has kept to the usual weather pattern found in south Texas, that is to say it has had very warm summers before cooling down slowly in the fall and then having milder winters. January is generally the coldest month, the average daytime temperatures being about the upper 60s and the night temperatures at times dropping into the 40s.
The UV Index is also a significant component of San Diego's weather. Historical climate data shows that UV levels are at their strongest during the summer months. The average UV Index reaches about 8 in July, that is, it comes under the Very High category. June and August have values of about 7, and May and September are generally also around 7. In fact, even in winter the average UV Index can reach approximately 4.
It does not follow that on a cooler day the level of UV exposure will be low. Temperature indicates how warm the air is, whereas the UV Index shows the strength of the ultraviolet radiation from the sun. They are two separate factors and both can be useful when arranging time spent outdoors.
When it is the hottest and most sunny time of the year, those who are outside for several hours should take special care of the UV Index at midday. Using sunscreen, wearing sunglasses, having a hat and having access to shade can make outdoor activities more comfortable and will help to reduce excessive UV exposure.
Rain also has an important effect on the local climate, since the historical averages indicate that the months of May and September get considerably more rain than some of the drier months. In some climate datasets, September has historically averaged about 5 inches of precipitation, even though in individual years it can be much wetter or drier.
Weather conditions can vary greatly from year to year and therefore long-term averages should be regarded as a guide not a prediction. It is possible to have a very hot summer, a wetter September or an unusually mild winter without altering the general climate pattern.
If someone is interested in the weather in San Diego, Texas, the best thing to do is to compare today's forecast with the historical data. The temperature, the amount of rainfall, the number of sunshine hours and the UV Index each contribute something different to the overall picture. It is particularly useful to check the UV Index before spending a long time outside during the brighter months, since UV exposure can become considerable even if the weather seems mild.
The weather in San Diego has clearly the characteristics of South Texas: hot summers, mild winters, variable rainfall and abundant sunshine throughout the year. When both the weather forecast and the UV Index are taken into account, residents and visitors receive a more comprehensive understanding of the outdoor conditions.