A lot depends on what your usual winter lows are. If you regularly go below -10, choices are pretty limited. Some possibilities:
r. keiskii is hardy to -15, evergreen and not over four feet.
r. luteum, -15, deciduous, will grow taller than four feet.
'Goldkrone', a good stong yellow that will not grow over 4', but not bud hardy below -10.
'Canary Islands' rated to -20, pale yellow, slow growing but ultimately more than 4'.
'Towhead', -15, pale yellow to 2'.
'Jericho', -20, pale yellow to maybe 3'
'Jenny Tabol', -20 pale yellow with pink in the throat, not over 4'
'Mary Fleming', -20 at least, not really yellow - more salmon and pink - but very reliable and easily kept below 4'.
I've undoubtably missed some, but these all do well in cold climates. Only Goldkrone is a true vibrant yellow. All look best in shade as strong sunlight bleaches the color.

The best hardy yellow azaleas are deciduous azaleas. Some examples are:

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"Girard's Yellow Pom Pom", -25F, 6', compact ,

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"Golden Lights" fragrant yellow, -40F, 4-5',

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"Lemon Lights" lemon yellow, -35, 4-5'

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"Sun Chariot", -25F buttercup yellow, 6', upright

"Marion Merriman", -25F, 5', wide growing
"Goldcrest", -25F, 4', compact.
"Weston's Lemon Drop" pale yellow, -35F, 3'

The so-called hardy yellow rhododendrons aren't that hardy and aren't that yellow.