Trigger Warning! descriptions of injuries and death! For example: mention of blood, burning, drowning, freezing, heatstroke, etc.
-0- side note before hand because it's technically relevant -0-
A state that's down south and almost always has hot weather would feel warmer to others and be affected by the cold easier, while a state up north with colder weather would feel colder to others and be affected by heat easier.
Fighting over thermostats and cuddles ensue
(Most people go to Alaska when they have a fever, and to Georgia when they're going through a cold front (they'd go to Florida but he's chaos and Texas is,, Texas. Besides, Geo has blankets))
Wisconsin: *opening all the house's doors and windows to enjoy the nice warm 60 degree weather*
Texas: *on the couch in a bundle of 5 blankets* how the fuck are you not dead
Florida: *next to Texas, trying to steal some blankets* Sconnie, I love ya dude but I will not hesitate to set this house on fire to warm up
-0- Colds/Flus -0-
The states can get sick two ways, outbreaks or just catching it.
Outbreaks
If there are a ton of outbreaks of something, for example: flu season, in their state there's a 50/50 chance they develop symptoms for however long the illness would last for someone who actually caught it. Though they'd suffer through the symptoms, they wouldn't actually have it and wouldn't be contagious or anything. But! Just because they're not contagious doesn't mean the other states wouldn't back up when they hear the news, being coughed on is still gross even if it doesn't endanger your health.
According to last year's report Louisiana had the most influenza outbreaks, followed by Arizona, Georgia, Hawaii, Idaho, Indiana, Kentucky, Mississippi, Nevada, Tennessee and Texas. So for that years flu season Louisiana would be sick and at least half of the others listed would also be sick.
Catching it
Now, they probably have really strong immune systems.
Or at least, they should but things can happen in the state that compromises that.
If there's a natural disaster, somethings changing in the state's government (new governor, new law, system change, etc), or there's riots impeding/distracting the state government their immune systems would be weak for however long it takes to readjust or fix the problem. During this time they can actually get sick, symptoms and all.
If this happened then the state would be contagious to the other states, immune system be damned. It'd be like when another person is sick, you have a chance of catching it.
On the rare occasion there'll be a state with a naturally horrible immune system (his name's Washington, someone please get him a cough drop and some water)
DC
He doesn't have people or land for outbreaks to affect him, only the government buildings.
Instead of having outbreaks he has government workers, if a handful of them or just the president gets sick he'll have the 50/50 chance of having symptoms.
Now, if the government is going through big changes or something is happening then DC will have a weaker immune system and would be able to get sick from the states. They honestly don't know if he could get them sick because he always self isolates and denies help when he is.
If there's some serious chaos going on with changes in government then he'll just straight up get sick. No catching it from anyone, nothing giving him a bug, he just develops symptoms of a really bad cold.
Recap:
Humans can't get states sick unless the state isn't at 100%, unless it's just an outbreak states can get other states sick no matter what, states can't get DC sick unless he's not at 100% leaving him as the designated caretaker when no one else wants to help (he would help regardless even if he could get sick, tis his job as parent friend)
-0- Hurricanes + Tropical Storms -0-
The way they affect the state depends how much damage was done and how their population reacts to it.
For example, a tropical storm or low level hurricane would maybe give Florida a bit of head rush or he'll get a little dizzy but nothing he can't ignore with a white claw. His people are used to them and honestly Don't Give A Fuck, if the house is fine and the car's still there we move on with our lives.
Then you have states that rarely get hurricanes and would panic when one hits, even if it's just a weak one. They'd have a headache, feel dizzy and sore.
Then there's higher level hurricanes, for those bruises will appear along with a migraine. Everything hurts and they're coughing up water, it's hard to breathe, and cuts from debris being thrown around by the winds are appearing everywhere.
In the end though, regardless of what scale it was, they're always left soaking wet and cold.
-0- Earthquakes -0-
First there's the feeling of a sea sick like nausea, that's the only warning they feel and only a few states (Literally just California and Alaska, someone please help them, the poor fault line babes) know how to recognize it instantly.
If they're outside of their own state then they'll get dizzy, balance is Gone and they fall over. If they're lucky enough to not hit their head or crash into something when they fall over then depending on the magnitude they could black out any number of times. I say black out and not pass out because while usually mixed up, blacking out doesn't always mean you loose consciousness.
Their vision goes completely, their eyes are open but all they can see is a dull black with staticky darker specks causing, well, static. They can't see if they try and if it's one of their first earthquakes they do try but it hurts to keep their eyes open, only worsening the feeling that their head is splitting open.
Sometimes their skin cracks. Sometimes if a highly urbanized area was hit and buildings go crashing they feel an invisible weight building up on their chest, it can lead to trouble breathing, or a broken rib, maybe multiple broken ribs.
-0- Fires -0-
There's two kinds of fires, fire season which is mostly for the western states and Florida who have the normal yearly stuff that the ecosystems need in order to function, and then there's when fires get out of hand and turn into disasters.
Fire Season:
Fevers that can range from low to high depending on how much land is burning, overheating when things, tiredness, dry skin, but overall manageable symptoms. Occasionally there are bad days but it's usually chill. It's not particularly nice, it sucks actually, but it's a yearly thing and they're used to it.
During the worse parts of fire season, for states with a ton of land on fire, smoke will come off them. They can suppress it but it takes a lot of energy. Statehouse living situation isn't the easiest because now it'd really suck to smoke out the house, others could get hurt, so they get good at minimizing it. (This mostly applies to California)
Irregular, Out of hand, or Man-Made:
A really high fever and burns slowly appearing everywhere. Smoke is harder to control and fills their lungs, making it hard to breathe. Sometimes they'll straight up faint, staying conscious while you're literally burning up isn't easy.
-0- Death -0-
They're immortal for as long as whatever they're a personification of exists. They can die just like any of person and it'll be painful but they always just,,, wake up. In the exact same spot they died except healed. If whatever killed them is still there then they'll die until it's over or someone saves them. If they die multiple times within a short period of time then every time they come back they'll have healed less and less.
-0- Leftover Stuff -0-
Floods = Initial flooding has them throwing up water and sometimes they can't breathe but afterwards it's more of just a cold, murky feeling in their chest (since these usually happen during big hurricanes just slap this on top)
Droughts = dehydration (dry skin, thirsty, insert symptoms of dehydration here)
Heatwaves = just, hot. For no reason. Air conditioning? Ice pack? Fan? Doesn't matter, they're hot.
Cold fronts = same story, different day. Blankets, jackets, and heaters don't matter or help much, they are cold. Depending how cold it gets and taking into comparison the usual temperature for their state they can develop hypothermia.
Tornadoes = Dizzy and disorientation. Bruises if they hit populated areas and destroyed stuff.
Dust Storms = trouble breathing, irritated eyes, more trouble breathing. Afterwards there's that feeling of when you went to the beach yesterday and suddenly there's the crunch of sand in your mouth.
Power Outage = they can't turn on or operate electric things, even living in the statehouse. For example, with the situation in Texas he wouldn't be able to turn on the lights, flipping the switch wouldn't do anything, but another state could do it for him (if they choose to help)