Types
Common Jasmine
Common jasmine or poet’s jasmine (Jasminum officinale), also called true jasmine, is a deciduous vine with clusters of starry, pure-white flowers that bloom all summer. It’s a twining climber with deep-green leaves that have five to nine leaflets, each up to 2-1/2 inches long. The very fragrant flowers are up to 1 inch in diameter.
Hardy to Zone 7, the vine grows vigorously (1 to 2 feet per year, up to 20 feet) and looks stunning climbing a large pergola, fence, or very large trellis. In the landscape, jasmine can also be pruned as a shrub near the house or near a walk so its intense fragrance can be enjoyed and so you can watch hummingbirds and butterflies come to the flowers. Common jasmine is native to Asia.

Winter Jasmine
Winter jasmine (Jasminum nudiflorum) is an “old-timey” shrub often found around Victorian homes. The beautiful yellow flowers are unscented, 1 inch wide, and they appear in winter or early spring before the leaves unfold. Winter jasmine is a good bank cover that will spread by rooting where the stems touch the soil. It is also very attractive when planted above retaining walls, with the branches cascading over the side. Hummingbirds love this vigorous vine!
Most other Jasminum species are semitropical vines, which are best planted in the spring after the danger of frost has passed.
Not a True Jasmine
Star jasmine, aka Confederate jasmine (Trachelospermum jasminoides), looks similar but is not a true jasmine. Hardy in USDA Zones 7B through 10, this native to China has phlox-like flowers that bloom on twining stems in spring and summer and are highly scented.
Comments
There are a couple of possible reasons. First, when you water, do it properly. Let the soil dry to barely moist before you water and then water deeply. Don't overwater!
Also, you may have spider mites. Look under the leaves for tiny specks. Either way, it may be healthy to give your plant a "shower." Spray the leaves with water (but not too hard) every few days. Keep checking for mites. If they are a continued problem, you may need more serious measures.

Hi Beverley,
Depending on where you live, you may need to cover or bring the plant indoors. Are you in a region where you experience constant freezing temperatures during the winter months? If so, bring the plant indoors. If you experience cold but not freezing temperatures, you can leave the plant outdoors, but covering it during cold nights is a good idea.