Answer:
It signals that the sentence will explain what Tamanika did despite the rain.
Step-by-step explanation:
"Although" is a subordinating conjunction that usually denotes the existence of an obstacle or some unfavorable conditions. However, despite them, the intented plan or an action has been performed.
Here, we see that Tamanika went for a walk despite the rain outside.
That means that this conjunction denotes an opposition between existing conditions and the outcome of the action. Conditions don't always need to be unfavorable, they only need to be opposite of the result. For example: "Although he had a clear shot, he missed the entire goal."