Hi Heather, thanks for writing to us on AskGuru.
The minimum rental period for all types of private properties is 3 months. However, most landlords prefer signing a 1 or 2-year lease.
You may want to consider renting a serviced apartment instead.
You will find our rental guide here useful: https://www.propertyguru.com.sg/property-guides/singapore-expat-renting-guide-36336
Hope this answers your question.