MetService says this weekend's the perfect time for those in the South Island to get out, before the weather takes a turn

Heavy rain watches are being issued for Marlborough, Canterbury, Westland, and Fiordland - starting tomorrow.

Conditions are forecasted to have a moderate chance of upgrading to a warning.

Meteorologist Clare O'Connor, says a low pressure-system from the Tasman sea is bringing unsettled weather.

She says that means rain in the coming days, and a change in temperature.