OK, it seems like too easy of a question.

To give it a bit of flavour I will ask how well are you usually prepared for it when the weather does change suddenly.

To start it off, temperature here dropped more than 40 degrees F. from yesterday, but most folks here are used to it doing stuff like that and have the clothing for it.
Since most of the drop was overnight very few were caught unaware.

60s during heat of day low 30s at night.
Living in the mountains storms can come in FAST, and you can see them come in too. It can go rain, hail, snow, and in cycles depending on the storm type, wind, etc.

Minnesota is know for it's changes in weather..i've come out of a movie in the winter to find the weather was much colder.
it was 20 below last week--35 today and down to 8 or so below
tomorrow..in the summer it's the thunderstorms that come up fast.
with the modern weather forecasts what would have been a fast change in the weather--morning to afternoon--is no surprise but
heavy winds over our lakes can come on very quick.out of a nice summer day a calm lake will go to whitecaps in minutes.
Lake Superior is a killer when it come to that.even the cottage country lakes will "stand on end" and drive fisherman to shore.

About ten years ago (in February IIRC) Tulsa set a record high in the low eighties during the day & had six or seven inches of snow and slush on the ground that evening. That was some WET, sticky snow. It just covered the front of my Bronco which mandated stops to clear the snow off the headlights every 15 minutes or so.

I stopped to get gas across the street from a local racket club. I was standing there in about six inches of slush with huge, wet snowflakes blowing by sideways. Some poor guy pulled up to the same set of pumps to get gas. He was dressed in exactly what you would expect someone playing tennis in eighty degree weather to be wearing.

He said he had been playing tennis and had stayed for dinner and drinks. When he came out he was greeted with about a -55 degree change in temperature and the lovely snow. All in all it was one of the most impressive displays of four letter vocabulary that I've witnessed.

If any of you are the guy in the white Acura Legend from 61st & Memorial ... Thanks for the laugh!

All my life, in Southern Illinois we have had a joke, that if you don't like the weather, wait 15 minutes!

Which was originally a quote from Samuel Clemins (aka Mark Twain) about the weather in NYC

No HUGE temp swings and the like, but it'll go from clear and warm, to raining, to clear and cold, to hot, to whatever, all seemingly in minutes - heck, if you're walking around town, you can be on one corner, and it's warm and calm, next corner, it's windy, cold, and damp

Yeah... the same is often said of the weather in Maryland. Between stuff coming over the mountains, and stuff coming up the bay, things can change quickly. Even in the summer I will tend to have a system jacket with fleece liner and nylon shell in the trunk. It can be rain gear, wind breaker, light warm jacket, or full winter coat, depending on what comes down the pike...

DFW metroplex weather:

Yesterday's high temp 80 degF
Today's projected high temp 80 degF
Tomorrow's projected high 38 degF with high winds.

Please make up my mind mother nature

I'm in Michigan.. We've gone from a Tornado Watch to a Winter Storm Warning in 24 hours. Its great!

Ok, it can change rather quickly.

Case in point... I'm heading from the Philly are to a spot just 2 hours away. The weather difference can easily be 10 degrees cooler in the other spot.

The weather on one side of the tunnel can often be quite different from the other. I can't begin to count how many times it would be raining on one side and sunny on the other. Snow on one, fog on the other... Etc...

Then, in the woods at the northern spot, a storm can blow through quite quickly and drop the temps down 20-30 degrees, then add in the wind chill.

Weather: You must respect it and be prepared for just about anything. Certainly helps to at least look at the weather trends and forecast before leaving home.

Temperature change...

I'll never forget the hike we took in college thru the "100 Mile Wilderness" in Maine. Much of it is in Baxter State Park, and it's the northern end of the AT, which terminates at the summit of Mt Katahdin. We were hiking at the base in cutoffs and t-shirts. By the time we were getting near the top of the Knife Edge trail, near the summit, we had taken every layer and scrap of clothing from our daypacks and put them on. The temp at the base was mid-70's, and sunny, and at the summit it was below freezing, a little sleet/freezing rain, and what seemed like 50 knot winds. That was in summer. I don't recall exactly what I had for extras, but, it was probably a wool sweater back then, a rain shell and wind pants. I always had a watch cap in the pack, and remember wearing my spare socks for mittens.

I've had similar experiences on other mountains, but, that was the one that I remember thinking, "I was swimming in the Penobscot River only about a mile from here earlier today in nothing but a smile, and now I wish I had my ski gear"

Ahhhh youth...

I was back in Iowa just before Christmas. Went to my sisters for brunch at 10am, and it was 46 (not bad for Iowa in Dec). We had breakfast and played some games and went out to help my brother in law with chores at 4 and it was 2 below (not windchill).

We can get some pretty big temperature swings out here in the desert too. It makes for some interesting hikes and hunting trips, that is for sure.

I've seen it change 30 degrees in less than one hour.
Very distinct cold front boundary.

Also have seen thunderstorm turn a 90 degree day into 40 degrees and hailing.

Keep your coat handy and don't roll your windows down too far if you're away from the car.

weather changes very fast here. Temperature fluctuate from +5 to - 10 in a day.

The temp will fluctuate faster outside the city by as much as 15 degrees celcius.

People have to dress in proper winter boots, clothes if they want to survive brutal wind, drifting snow.

In Iowa it can vary quite wildly. Just last week we had a 50F difference in Low temperatures from one day to the next (-20F to 30F). The high on the second day was in the mid 40s! Then we can throw in the whole, tornados and flood watches to blizzard warnings in a single storm thing.

- Eric