Tracking another warm and sunny day ahead of a stout cold front and chilly showers by late Saturday
October is certainly showing us that it isn't ready to act like October just yet.
After another round of record-setting warmth, we're staying remarkably mild for the middle of the week with sunshine, light winds and afternoon temperatures running well above normal. In fact, Idaho Falls will remain in that 77-to-79-degree range through Friday, with several other lower-elevation communities also pushing well into the 70s.
But enjoy it while it lasts.
A significant weather pattern change arrives this weekend. Temperatures will begin falling Saturday, and by Saturday night we're looking at a 70% chance of showers and thunderstorms across parts of eastern Idaho. That moisture continues into Sunday and Monday, bringing a much more unsettled feel to the region.
Higher elevations will be cold enough for mountain snow, while valley locations deal primarily with rain and a few thunderstorms. This is the kind of setup where Saturday afternoon can still feel relatively mild, but by Sunday it will look and feel much more like fall.
WEDNESDAY — ANOTHER WARM, BEAUTIFUL OCTOBER DAY
Idaho Falls: 78° | Overnight low: mid-40s
We're starting the day cool enough for a jacket, but sunshine quickly takes over.
Expect mostly sunny skies with temperatures climbing through the 50s during the morning and into the 60s around lunchtime. By afternoon, we're pushing the upper 70s.
Winds stay light, so this should be a comfortable day for outdoor work, walking, golfing, yard projects, running errands or getting one more taste of summer before the weather pattern changes.
Lifestyle forecast:
Morning commuters will want a jacket or light sweatshirt, but you may be carrying it by afternoon. Sunglasses and short sleeves make sense later in the day.
For the mountains and western Wyoming, conditions remain pleasant but cooler. Jackson and the surrounding valleys will have cooler mornings, while sunshine keeps afternoon temperatures comfortable.
Wednesday weather message:
Cool morning. Warm afternoon. Sunshine all day.
THURSDAY — WARMTH CONTINUES
Idaho Falls: around 77° | Overnight low: mid-to-upper 40s
Thursday looks remarkably similar.
Mostly sunny skies and light winds will dominate, with another afternoon in the upper 70s. The morning will have more of an October feel, but by afternoon you'll be wondering where fall went.
Pocatello and the lower Snake River Plain will again be among the warmer areas.
Across western Wyoming, temperatures will be noticeably cooler than eastern Idaho, but still mild for early October. Jackson and the higher valleys will have crisp mornings followed by pleasant afternoons.
Lifestyle forecast:
This is a good day to take advantage of the weather. Outdoor lunch? Absolutely. Fall yard cleanup? Perfect. Mountain drive? Great opportunity before the weekend weather change.
If you're heading into the mountains, remember that temperatures can drop quickly after sunset.
Thursday weather message:
Another warm one — but the countdown to the weekend change has begun.
FRIDAY — LAST TASTE OF SUMMER
Idaho Falls: 79° | Overnight low: upper 40s
Friday may be the warmest and most important day of the extended forecast because it could be the last truly warm day for a while.
Look for sunshine, very mild temperatures and generally light winds during the first half of the day.
Temperatures climb into the upper 70s, with some lower-elevation communities potentially reaching around 80 degrees.
That makes Friday the day to get outside if you can.
Have outdoor plans? Take advantage of them.
Planning a mountain drive, golf, football tailgate, hike or fall gathering? Friday looks like the best bet of the period.
But you'll notice the atmosphere beginning to change later as the next weather system approaches.
Friday night:
Clouds increase and temperatures begin falling. The wind may also become more noticeable as the weather system gets closer.
Friday weather message:
Summer's encore performance — don't waste it.
SATURDAY — THE WEATHER TURN BEGINS
Idaho Falls: around 70°
This is where the forecast changes.
Temperatures fall roughly 8 to 10 degrees from Friday, and clouds become more common as the next system moves toward the region.
Instead of upper-70s sunshine, we're looking at a cooler, increasingly unsettled Saturday.
There may still be periods of dry weather, especially early in the day, so outdoor plans aren't necessarily a washout. But conditions become less predictable as we head toward Saturday evening.
The biggest concern comes Saturday night.
SATURDAY NIGHT — 70% CHANCE OF SHOWERS & THUNDERSTORMS
Rain chances increase substantially Saturday evening and especially overnight.
We're watching for showers and thunderstorms, with wet weather becoming increasingly likely as the system moves into eastern Idaho and western Wyoming.
Some storms could produce locally heavier rain and gusty winds.
The mountains will be a completely different story.
As colder air arrives, snow levels begin dropping, meaning precipitation that falls as rain at lower elevations can become snow at higher elevations.
Saturday night weather message:
The summer-like pattern breaks — rain and storms move in, and mountain snow becomes increasingly possible.
SUNDAY — A VERY DIFFERENT DAY
Idaho Falls: mid-to-upper 50s
Sunday is where you'll really notice the change.
Instead of sunshine and temperatures near 80, we're looking at a much cooler, cloudy and unsettled day.
Rain is likely, with additional showers and thunderstorms possible during the day. Current guidance puts precipitation chances around 70%, making Sunday the wettest and most unsettled day of the weekend.
Temperatures may struggle to get much beyond the mid-50s in Idaho Falls.
That's a dramatic change of roughly 20 degrees from Friday's high.
WESTERN WYOMING
Western Wyoming gets an even stronger dose of fall.
Jackson, Star Valley and the surrounding mountains will turn considerably colder, with rain in the valleys and snow becoming increasingly likely at higher elevations.
This is a weekend to pay attention to elevation.
A sunny 70-degree Friday in Idaho Falls can become a cold, wet or snowy mountain experience just 50 or 100 miles away.
Sunday lifestyle forecast:
This is the day for football on TV, a warm drink, a hoodie, a rain jacket and indoor plans.
If you're attending an outdoor event, prepare for wet and chilly conditions rather than the warm weather we've become accustomed to.
If you're driving through the mountains, check conditions before leaving and allow extra time.
Sunday weather message:
Fall finally arrives — cooler, wetter and much more unsettled.
MONDAY — SHOWERS HANG AROUND
Idaho Falls: low-to-mid 50s
The unsettled pattern doesn't immediately disappear Monday.
We could see additional showers and perhaps a few thunderstorms, with plenty of clouds and temperatures remaining much cooler than the first half of the week.
Mountain snow remains possible at higher elevations as colder air settles into the region.
Monday could feel like a completely different season compared with the 70s and 80s we've experienced recently.
Don't be surprised if you're reaching for the heavier jacket Monday morning.
THE BIG TEMPERATURE CHANGE
Here's the simplest way to tell the story:
WEDNESDAY: ☀️ Upper 70s
THURSDAY: ☀️ Upper 70s
FRIDAY: ☀️ Around 79°
SATURDAY: 🌥️ Around 70°
SATURDAY NIGHT: 🌧️ 70% showers/storms
SUNDAY: 🌧️ Mid-to-upper 50s
MONDAY: 🌧️ Low-to-mid 50s
That's roughly a 20-to-25-degree drop from the warmest afternoon to the coolest part of the weekend.
And it's not just a temperature change.
We're going from:
SUNSHINE → CLOUDS → RAIN → THUNDERSTORMS → MOUNTAIN SNOW → COLDER AIR
That's a legitimate pattern change.
WHAT THIS MEANS FOR YOUR WEEKEND
🚗 TRAVEL
Friday is the easiest travel day.
Saturday becomes increasingly unsettled, particularly late in the day. Sunday and Monday will require more patience, especially for mountain travel.
Higher passes and mountain roads can become wet or snow-covered as snow levels fall.
🏈 FOOTBALL & OUTDOOR EVENTS
Friday and early Saturday offer the best outdoor conditions.
If you're going to a football game, tailgate or outdoor event Saturday, dress for changing weather. A light jacket in the morning could become a rain jacket by evening.
Sunday is a very different proposition: chilly, wet and much less comfortable for extended outdoor activities.
🍂 FALL COLORS & MOUNTAIN DRIVES
The warm weather has been great for getting outside, but this weekend's system will bring the first significant taste of colder fall weather.
If you're heading toward Jackson, Teton Valley, Island Park or the higher elevations, don't dress based on what the thermometer says in Idaho Falls.
Dress for the mountains.
🧥 WHAT TO WEAR
Wednesday-Friday: Light jacket in the morning, short sleeves possible in the afternoon.
Saturday: Layers. Keep a rain jacket nearby.
Sunday-Monday: Jacket, hoodie or heavier layers, with rain gear increasingly important.
Mountain travelers should be prepared for significantly colder conditions and the possibility of snow at higher elevations.
THE BOTTOM LINE
Enjoy the next three days.
We're still living in the warm side of October with sunshine and upper-70s temperatures continuing through Friday.
But the atmosphere is already preparing to flip the script.
Saturday brings the transition, with temperatures falling toward 70 and showers and thunderstorms becoming more likely Saturday night.
Then Sunday and Monday look much more like fall — cooler, wetter and unsettled, with rain in the valleys and snow possible in the mountains.
So if you've been putting off the fall chores, outdoor projects or that last round of golf, Thursday and Friday are your window.
By Sunday, you'll probably be looking for the hoodie, the rain jacket — and maybe the first real fire in the fireplace.
Stay with Local News 8. We're tracking the weekend storm system, the temperature drop and the first meaningful chance of mountain snow.
