it keeps thunderstorming in summer until the season ends.

Some worlds (Brindleton Bay and Willow Creek, for example, especially Brindleton Bay) just have awful weather in the summer.  Oasis Springs doesn't have thunderstorms.  Sulani has them in the winter.

If you hate thunderstorms you can turn them off in game options. You can also use and abuse Dr June's Weather Machine, or have a mermaid in your household.

(P.S.  I feel you; I've considered turning them off because my Sims' pets are afraid of thunderstorms!   But I think this is intended behavior.)

Brindleton Bay and Windenburg are not the places you want to be if you want to enjoy summer, but your Guaranteed a hot summer, playing Oasis Springs or Strangerville. Newcrest can also be quite hot half the days as well as Willow Creek.

@chillaxbruhz , in addition to what @Citysim9997 and @xochiquetzl_xkvn have mentioned, I wanted to add that not every part of the world has hot weather in the Summer.  This is why different worlds will have different weather during a particular season.🥰  Where I live it is usually very hot (but it will occasionally storm) in the Summer.  But our storms are mostly in the Spring.  However, when I visited Florida in the Summer it stormed every afternoon and was still hot!. 😅

Also, depending on how long your seasons are set to might effect your weather as well.  Since the beginnings and ends of seasons tend to transition from and to the next season, having a shorter season (like for only one week) can tone down the weather you see in that season a bit. 😉

@PugLove888  Yes, this. My ex was from Florida and insisted that in Florida the sky just opens up every day at 4pm, like clockwork, and when I visited it seemed to be true.

 I like having a mermaid in the household or Dr June’s Weather Machine to make it stop when I’ve had enough, and to keep a supply of napnip for the cats. I wish dogs had an equivalent.

@xochiquetzl_xkvn , yes!  Right around 4 pm!!! We could always tell time by the clouds! 🤣  Good thing the storms didn't last long!  I hope some day to go back to the Keys for a vacation! 💗  Orlando was fun, but without the sea breezes that the Keys have, the hot humidity is unbearable to me!🥵😅 

I remember having my Sims who lived in stormy worlds learn the Wellness skill (if you have Spa Day) .  That seemed to help a lot! I haven't tried it in a long while though because I keep playing Winter! 🥳

Popped this thread into general discussion and feedback as it is an intentional design feature, not so much a bug. I can confirm, we get massive storms here in Austin during the summer! Had one the other night.

@PugLove888  Yeah, Wellness helps a lot with tense moodlets.  But the mermaid weather control is SUPER CLUTCH.  I've never had a mean or evil mermaid because they can't clear skies and that's my #1 most used mermaid power!  :D

Also, napnip.  THE BEST.  Love it!  (So do the Sim cats who go from tense to chill with a single treat.)

@EA_Arcadia  Yeah, I used to live in Dallas and we got nasty storms sometimes, too, with flash floods.  Also strings of 100 days in a row over 100, and people used to keep telling me "But it's actually HOTTER in [insert some town up north here] because Texas is a desert and HAS NO HUMIDITY!" 

Insert mirthless laugh here.

(Note to non-Texans:  WEST TEXAS is a desert.  The rest of (majority of) Texas is a very hot prairie with high humidity.  Not Florida high, but, say, 30-35%.  104F + 35% Humidity = "Heat Advisory, please stay indoors, life threatening danger to the elderly, children, and pets.")

@xochiquetzl_xkvn , yes, I think a lot of people forget about the Wellness skill helping with tense moodlets because Spa Day was one of the first packs we ever got.  While it was pretty popular when when the Sims 4 started, I think a lot of people forgot about it when newer packs came out.  

I seem to have some Sims have a harder time with storms in the game than other Sims.  Some of them go to bed or do other activities (as long as they are inside) no problem, while others it is hard to get them do anything.  I'm sure it has to do with their other buffs at the time of the storm.  

I haven't played a Mermaid in a while, but you are making me want to again! 😂🧜‍♂️🧜‍♀️

I do wish there was something like Napnip for dogs in the game!  

I grew up in the Dallas area! 🥰 Yes, we would get some summer storms, but mostly it was hot and humid with high pressure sitting on top of us.🥵  Most of the bad storms would happen in the spring!  May can be especially bad! 😬  And you are so right!  Too many people think all of Texas is a desert!  Dallas and Fort Worth are prairies , the coastal areas being even more humid and having palm trees, and east Texas has a lot of pine trees (you'll often hear it being referred to as the Piney Woods!) 🤣

@PugLove888  Play a mermaid, just for the weather control!  :D

Yeah, like people, some Sims seem more prone to be afraid of storms than others. 

I love Spa Day.  Okay, I seldom go to the spa, oops, but I do have my Sims do yoga and meditate.  I love that they can teleport to Forgotten Grotto or Sylvan Glade while meditating!

Depends on where your Sims live, and it's different every year. Live in Oasis Springs or Sulani if you want summer all year long. I do hope they reduce thunderstorms in Granite Falls.