National Weather Service Forecast for: Bay St. Louis MS
Issued by: National Weather Service New Orleans/Baton Rouge, LA
Updated: 2:01 am CDT Jun 30, 2026
 
Overnight

Overnight: Clear, with a low around 79. West wind around 5 mph.
Clear

 Tuesday

Tuesday: A 30 percent chance of showers and thunderstorms, mainly after 5pm. Sunny, with a high near 92. Heat index values as high as 105. Northwest wind around 5 mph becoming calm.
Sunny then
Chance
T-storms
 Tuesday
Night
Tuesday Night: A chance of showers and thunderstorms before 11pm, then a slight chance of showers and thunderstorms after 4am. Partly cloudy, with a low around 79. North wind around 5 mph. Chance of precipitation is 30%.
Chance
T-storms
 Wednesday

Wednesday: A chance of showers and thunderstorms before 3pm, then a chance of showers and thunderstorms after 5pm. Sunny, with a high near 89. North wind 5 to 10 mph becoming southeast in the afternoon. Chance of precipitation is 30%.
Chance
T-storms
 Wednesday
Night
Wednesday Night: Partly cloudy, with a low around 80. Southeast wind around 5 mph becoming calm in the evening.
Partly Cloudy

 Thursday

Thursday: A slight chance of showers before 10am, then a slight chance of showers and thunderstorms between 10am and 1pm. Sunny, with a high near 89. Northeast wind 5 to 10 mph becoming southeast in the afternoon. Chance of precipitation is 20%.
Slight Chance
T-storms
 Thursday
Night
Thursday Night: Mostly clear, with a low around 79. South wind around 5 mph becoming calm in the evening.
Mostly Clear

 Friday

Friday: Sunny, with a high near 90. North wind around 5 mph becoming south in the afternoon.
Sunny

 Friday
Night
Friday Night: Mostly clear, with a low around 80. South wind around 5 mph becoming west after midnight.
Mostly Clear
Lo 79 °F Hi 92 °F Lo 79 °F Hi 89 °F Lo 80 °F Hi 89 °F Lo 79 °F Hi 90 °F Lo 80 °F

Heat Advisory
 

Overnight
 
 Clear, with a low around 79. West wind around 5 mph.
Tuesday
 
 A 30 percent chance of showers and thunderstorms, mainly after 5pm. Sunny, with a high near 92. Heat index values as high as 105. Northwest wind around 5 mph becoming calm.
Tuesday Night
 
 A chance of showers and thunderstorms before 11pm, then a slight chance of showers and thunderstorms after 4am. Partly cloudy, with a low around 79. North wind around 5 mph. Chance of precipitation is 30%.
Wednesday
 
 A chance of showers and thunderstorms before 3pm, then a chance of showers and thunderstorms after 5pm. Sunny, with a high near 89. North wind 5 to 10 mph becoming southeast in the afternoon. Chance of precipitation is 30%.
Wednesday Night
 
 Partly cloudy, with a low around 80. Southeast wind around 5 mph becoming calm in the evening.
Thursday
 
 A slight chance of showers before 10am, then a slight chance of showers and thunderstorms between 10am and 1pm. Sunny, with a high near 89. Northeast wind 5 to 10 mph becoming southeast in the afternoon. Chance of precipitation is 20%.
Thursday Night
 
 Mostly clear, with a low around 79. South wind around 5 mph becoming calm in the evening.
Friday
 
 Sunny, with a high near 90. North wind around 5 mph becoming south in the afternoon.
Friday Night
 
 Mostly clear, with a low around 80. South wind around 5 mph becoming west after midnight.
Independence Day
 
 A chance of showers and thunderstorms after 1pm. Sunny, with a high near 90. Light and variable wind becoming south 5 to 10 mph in the afternoon.
Saturday Night
 
 A slight chance of showers and thunderstorms. Mostly clear, with a low around 79. South wind around 5 mph becoming west after midnight.
Sunday
 
 A chance of showers and thunderstorms. Mostly sunny, with a high near 89. West wind 5 to 10 mph becoming south in the afternoon.
Sunday Night
 
 A chance of showers and thunderstorms. Partly cloudy, with a low around 80. Southwest wind 5 to 10 mph.
Monday
 
 A chance of showers and thunderstorms. Mostly sunny, with a high near 88. West wind 5 to 10 mph becoming south in the afternoon.

 

Forecast from NOAA-NWS for Bay St. Louis MS.