Washington does not actually exempt itself from daylight saving time, but has made repeated legislative efforts to do so—the simple reason being that state lawmakers and many residents dislike the twice-yearly clock changes and prefer either permanent standard or daylight time for public health and convenience. However, under federal law, states can only exempt themselves by staying on standard time year-round, not by choosing permanent daylight saving time without special Congressional approval.
The other U.S. state that actually does not observe daylight saving time is Arizona (except for the Navajo Nation). Arizona long ago opted to remain on standard time all year, mainly because the extra daylight would make the hot summers even longer and less bearable. Hawaii also does not observe daylight saving time, due to its tropical latitude making daylight shifts less useful.
Summary Table
The core reason is legal simplicity and local preference: federal rules demand either the biannual switch or permanent standard time. Arizona and Hawaii have simply chosen to stick to standard time year-round, avoiding the confusion and inconvenience of clock changes.
SOURCES
(https://www.axios.com/local/seattle/2024/01/23/daylight-saving-debate-washington-seattle)(https://en.wikipedia.org/wiki/Daylight_saving_time_in_the_United_States)
(https://www.seattletimes.com/seattle-news/politics/daylight-saving-time-even-the-cows-dont-like-it-says-state-senator-trying-to-eliminate-it/)
(https://www.transportation.gov/regulations/daylight-saving-time)
(https://www.ncsl.org/transportation/daylight-saving-time-state-legislation)
