I think it will be fine; it might lose all the leaves and look pretty bad, but if you water it about once a week, the roots will be fine.
We had a really severe drought last summer, everything was brown and crunchy (including the wisteria) by the end of August. It rained a little in September and October and in November the wisteria was trying to bloom again. Finally when it got cold in January, the wisteria calmed down and settled in and got back on its cycle by bloom time in April. Try and keep the roots alive and chances are that's what it's trying to do anyway, losing the leaves so it can concentrate on saving its own roots. I think it will survive till November.
