Well, yeah, kinda... but screw it. :D

Weather.com predicts 90F temperatures in the day with a 40% chance of thunderstorms early in the day on Thursday the 4th. Drops to the low 70s at night, 30% chance of rain.

But that'll change by the 4th. Forecasts always do this far out. Also, there's still the rest of the con. But I think one lesson is clear, less so from the forecast and more from general experience of Indiana in August: It'll be hot, humid, and one day holds a fair chance of heavy rain. Not a bad idea to keep that in mind when planning. 

Glad I have a connected hotel.

I feel like Gen-Con is always hot, humid, and has one day with a random rainstorm.  Well except last year where for obvious reasons it was downright acceptable, albeit still hot.

Yeah, I know, that prediction isn't surprising, is it? :D

Please don't jinx things. Please.

No weather prediction more than 48 hours in advance is valid.  Even 24 hours isn't that reliable.  Don't look at the weather reports until next Tuesday.

According to NOAA, this week the highs are in the low 80s and go down to 65.  I cannot wait for that kind of weather to return here.

Not sure I've ever considered bringing an umbrella to Gen Con - I don't think I'd want to wander around so many expensive paper products with a drippy umbrella. Rainy days are "let's stay in the skywalks" days for me.

According to my local weatherman this morning the forecast for Gen Con is

Thurs High of 92 24% chance of rain
Fri     High of  91  24% chance of rain
Sat    High of 91 32% chance of rain
Sun   High of 91 20 % chance of rain 
 

I've never needed a jacket outside for Gen Con.  But I often do appreciate a sweatshirt inside.  The event spaces can get pretty chilly.

+1 on an umbrella.  If you're worried about books in your backpack get a rain cover for it, or wrap the books in a plastic bag - trash bags work fine.

But yeah, it's shaping up to be a hot one.  Plan your costumes accordingly.

I agree. It's much colder inside the convention center than outside. Outside, it's t-shirt and shorts weather. inside, it's sweater and jeans weather.

It always amuses me how much temperature sensitivity varies by person to person. I consider the interior of the convention center to be slightly uncomfortably warm, and outside to be miserably so. For me 65 F is nice summer shorts/swimming weather, and there's no need to break out jackets or long pants for warmth until you hit the 40s (F). If it gets below freezing I might consider a light hat or zipping up a windbreaker.

I've spent years living in places where negative 30-35 F was a normal winter temp.

I have lived in the Ohio valley my whole life and never have been able to take the heat. Luckily, my wife is also a winter person.

It really does boggle the mind in the Exhibit Hall when I am wiping sweat off my forehead and I see people wearing sweatshirts and backpacks.  I would probably pass out after 15 minutes in that outfit

I'm more with helenbb: I freeze my rear off in the ICC and need to step outside regularly. 

Yeah, I'm amazed by the range of sensitivities too. I work with the entire range: People who freeze like me with people who sweat in the exact same room. It's nuts. 

A 10 day forecast is a historical forecast of what those days have looked like over the past 50+ years. A five day forecast is actually looking at what weather fronts are doing and where they may go. A three day forecast is about as good as it gets. With that being said, checking the good ol' Weather.gov- looks like mid 90's for highs, mid 70's for lows, and a good chance of thunderstorms (the good ol' midwest pop up thunderstorms). The highest chance of thunderstorms will be in the afternoon. Conductive buildup due to the cooling of the upper atmosphere and the ground releasing all the heat it soaked up during the day. Basically, warm air rises. cold air sinks, that causes friction and an electrical charge builds up. Lots of moisture in the air grabs dust and whatever else is floating around in the sky, and the next thing you know, you have a towering cumulus cloud making a nice anvil shape and BOOM! Thunder and lightning, very very frightening. And rain, possibly even hail. Fun stuff! Weather in the midwest during the summer is awesome!