The Centers for Medicare & Medicaid Services (CMS) said on September 28 that the national average Medicare Advantage (MA) premium is projected to fall in 2027, while the stand-alone Part D drug-plan average is projected to rise less than $1 a month. Open Enrollment, when people can change plans, runs October 15 to December 7.
What CMS projects
CMS calls its national figures projected. It puts the weighted average monthly MA premium at $12.00 in 2027, down from $14.37, and the stand-alone drug-plan average at $36, up from $35.09.
Arizona's figures, from CMS's Arizona sheet: 1,560,534 people are enrolled in Medicare. The average monthly MA premium is $4.47 for 2026 and $2.81 for 2027. There are 148 MA plans in 2027, against 133 in 2026; the lowest MA premium is $0. Nine stand-alone drug plans are offered, from $5.30 a month.
What changes on January 1
2027 coverage begins January 1. CMS's April 6 rate announcement sets the annual out-of-pocket threshold in the standard Part D benefit at $2,400, up from $2,100, and the deductible at $700, up from $615. Medicare.gov says no drug plan may have a deductible above $700 in 2027, and some plans have none. It also says that once a person's out-of-pocket spending on covered drugs reaches the threshold, catastrophic coverage starts and covered drugs cost nothing out of pocket for the rest of the year.
What an average does not tell you
An average premium is not your premium. CMS's national figure is a weighted average; the release does not say how it is weighted. The Arizona sheet says 38.67% of people in a stand-alone drug plan have access to a plan with a lower premium than they paid in 2026. That describes access to a cheaper plan, not a change in anyone's own premium. CMS says about eight in 10 MA enrollees can keep their plan at the same or a lower premium.
Medicare.gov says drug plans can change their drug lists during the year and must notify you of changes affecting drugs you take. Federal rules require MA plans to notify enrollees when a contracted provider is terminated.
The dates and what to do
CMS's timeline has plans start notifying enrollees of 2027 changes in September and the Medicare.gov Plan Finder, a plan-comparison tool, carrying 2027 plans by October 1. Medicare.gov says a plan must receive an enrollment request by December 7 for a change to start January 1. CMS says people who want to keep their current coverage generally do not need to re-enroll.
Medicare.gov advises reviewing the Annual Notice of Change, which lists coverage and cost changes taking effect in January; if it has not arrived, contact the plan. CMS also points to the Plan Finder and to 1-800-MEDICARE, which Medicare.gov lists as 1-800-633-4227. Medicare.gov lists State Health Insurance Assistance Programs for free health insurance counseling.