It doesn't matter where you are in the world, even in climates that are usually quite dry like Texas; rain is going to play a factor in your shipping and delivery needs at some point in time. What you absolutely do not want is for the one time you don't worry about the weather playing a factor in your deliveries for that to be the time that it does in fact rain. That is why it is important that any Dallas courier service that you do business with is competent at making sure that your goods are always protected from the elements. While some responsibility for this must absolutely lay on you, the shipper, it is also important that your delivery company is handling your packages properly and not needlessly exposing them to the elements, something you shouldn't be afraid to inquire about, especially if what you are transporting is in fact something that could become seriously damaged by the rain.
When you're looking for a delivery company that will serve you best, you want a company that always puts professionalism at the forefront of all of their activities. This means that they are always going to put customer service before everything else in their operations, which will give them a very empathetic point of view when it comes to realizing how important it is to protect your shipments from the weather. There are many things, such as documents, which even the slightest bit of moisture could render completely unusable, and this could cause real problems for your business if it delays a transaction or a signing you are attempting to complete. A courier company that understands and respects the seriousness of your business is going to help you make sure that something like that never happens, even if it's raining.
Of course, you have to assume some of the responsibility for protecting your goods from the rain as well. You have to ensure that any items which could be damaged by rain or snow are completely sealed and protected inside their packaging, because even the most solicitous courier is likely to be unable to completely protect your shipment from seeing any rain at all if it is raining in earnest. However, if you take every possible precaution yourself when it comes to packing, then your courier should be able to take your package the rest of the way without it sustaining any rain damage.