Springtime in Tx usually starts about mid March, wildflowers are spectacular ( before the summer dry knocks them back ).
Any rains are just beneficial for artifact surface hunters.
best bet to go home with some very worthwhile artifacts is go on a screen dig. ( you get what you pay for )...call the operators when you actually have a
fixed date for your visit...Some sites dont last long so no sense calling too far in advance..
For the absolute most economical best bang for a buck, the Chrstners ranch dig near Waco Tx is unbeatable. All day $40 per person, plus...free camping with your paid day if thats your thing.
Caution...artifact hunting in Tx can be addictive, just had 2 Floridians drive over to the most recent Juno dig.