There is no rent control in Washington State. A landlord can raise the rent as much as they want in most situations.
However, if you miss a rent payment, you have the right to a payment plan. In some counties, the landlord must also offer you a chance for mediation.
In any situation, you can try to negotiate with the landlord not to raise the rent for a certain period of time. If you and the landlord do agree to this, try to get it in writing.