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Time difference: Spearfish-South Dakota to Udon Thani
SPF (Black Hills Airport-Clyde Ice Field) → UTH (Udon Thani Airport)
+13h
Udon Thani is ahead
13d
est. jet-lag recovery, eastbound
Reading the clocks
When it's noon in Spearfish-South Dakota, it's 1:00 AM in Udon Thani. Good for planning calls home or coordinating with people on the other end.
Jet lag outlook
Significant jet lagCrossing 13 time zones eastbound — plan roughly 13 days to feel fully adjusted. Shifting your sleep schedule 3 days before departure helps.
Frequently asked questions
What is the time difference between Spearfish-South Dakota and Udon Thani?
Udon Thani is 13 hours ahead of Spearfish-South Dakota.
How bad will my jet lag be?
Crossing 13 time zones eastbound typically takes 13 days to fully adjust to. Eastbound trips (traveling against your body clock) tend to feel worse than the same distance westbound.
What is the flight time from SPF to UTH?
The nonstop flight distance is 7,846 miles. See the full distance and flight-time breakdown for exact timing.
What's the best way to book around jet lag?
Overnight eastbound flights that land in the morning let you push through to local bedtime and adjust faster. Call CheapoTrav — our agents know which schedules on this route land at the best local time, plus unpublished phone-only fares.