The f0 peak sometimes occurs after the syllable with which it is associated, and the peak alignment varies, depending on several factors such as lexical tone target, neighboring tones, focus, and so forth. This study investigates the effect of weak tones on the alignment of f0 peaks with three tone types (i.e., H, M, and R) of South Kyungsang Korean, spoken in the southeastern part of Korea. When three tone types are followed by one or two unstressed suffixes, R was found to have the maximum amount of peak delay and M was found to have the minimum amount, i.e., the peak came in the second syllable, following the R‐toned syllable, but the peak came in the syllable following the H‐toned syllable. This peak delay was not found for M. Thus, it is argued that the tone alternation patterns in suffixed words are not random; rather, they systematically reflect the phonetic implementation of each tonal target. For example, the peak is in the final portion of a syllable in R, and it takes more time for the peak to be fully realized. This effect can be clearly observed when the following tone is weak.