water or weather causes vasoconstriction
of blood vessels leading to numbness
of body parts.
This is seen in neuropathy or temporarily due to vasoconstriction.
Sometimes this is also seen in "Raynaud's phenomenon" where there is abnormal response to cold exposure due to spasms of blood vessels supplying hand.
Keep your body warm by covering it with warm clothes. If it persists , Vitamin B12
supplements will help you regain your strength and remove the numbness.
Hope this answer helps you.
Wish you a good health.