Fall in Irkutsk arrives fast, shifting from those surprisingly mild September afternoons to nights that freeze solid by November. You’ll see average highs tumble from the mid-60s °F at the start of autumn down to the mid-teens °F by the time the season wraps up.
Lows drop right along with them, often dipping below freezing well before October is over. This dramatic drop really sets the mood—fall here feels brief, brisk, and honestly, pretty Siberian.
Clouds start rolling in more as autumn goes on, and daylight shrinks by more than five hours from September to November. Rain doesn’t stick around long, usually giving way to the first real snow by late fall.
The air stays dry, but the cold settles in quickly, so if you’re planning to be outside, you’ll want to dress warm.
If you know what to expect, you can actually enjoy both the beauty and the challenges of autumn in this part of Siberia. With a little luck, you might catch some cool, clear days early on, or maybe you’ll be around for those first snows that signal winter’s on the way.
Irkutsk Fall Climate Overview
Irkutsk goes through a sharp seasonal change in autumn. Temperatures drop fast, days get shorter, and rain gives way to snow before you know it.
The city’s location inland and its elevation both play a part, making the weather here pretty distinctive compared to other parts of Russia.
Continental Climate Characteristics
Irkutsk sits in a humid continental climate zone with those classic long, cold winters and short, warm summers. Fall acts as the big transition, and you’ll notice the cooling trend right away in September.
Average daily highs start at about 66°F (19°C) in early September and plummet to near 16°F (-9°C) by late November.
Nighttime temps fall even faster, often dropping below freezing by mid-October. Since Irkutsk doesn’t get any help from the ocean, heat escapes fast, and you get some pretty wild swings between day and night.
Cloud cover steadily increases. In September, you’ll see partly clear skies almost half the time, but by late November, overcast days take over.
That means less sunshine, and honestly, it makes the air feel colder than the numbers might suggest.
Humidity stays low, so muggy days are pretty much unheard of. Instead, you get that signature dry chill—definitely the defining feature of fall weather here.
Geographical Influences on Weather
Irkutsk sits near Lake Baikal, but not right on the shore. The lake does help a bit, slowing down the arrival of extreme cold compared to places further inland.
Still, the effect isn’t huge, and the city cools off fast once autumn begins.
At about 433 meters (1,421 feet) above sea level, Irkutsk is high enough that nights get especially chilly. Cold air settles into the valleys, so frost can show up earlier than you’d expect.
Since the region sits deep in Siberia, no ocean currents or maritime winds ever reach it. This isolation creates a true continental pattern, with sharper seasonal changes than you’d get in western Russia or by the coast.
All these factors combine to give Irkutsk that brisk, early-frost feeling, with winter knocking on the door before you know it.
Seasonal Weather Patterns
Precipitation shifts a lot during the fall. September still brings some light rain—about 2 inches for the month.
By October, rain drops off, and the first snows start to show up. In November, snowfall averages around 1 to 1.5 inches in a 31-day stretch, pretty much replacing rain altogether.
Daylight fades fast. Early September gives you over 13 hours of light, but by late November, you’re down to just over 8 hours.
Sunrises get later, sunsets come earlier, and your window for outdoor activities shrinks.
Winds stay moderate, averaging about 6 mph, usually from the west. They’re not wild, but that breeze can make the cold feel even sharper, especially late in the season.
By November’s end, you’ll find yourself in almost full winter mode—frozen ground, steady clouds, and plenty of subfreezing days.
Average Fall Temperatures in Irkutsk
Fall in Irkutsk means temperatures drop fast, shifting from those last hints of summer to the first real taste of Siberian winter. You’ll see daily highs and lows slide down steadily, and frost and snow get more common as the weeks go by.
Monthly Average Temperatures
In September, average high temperatures hit about 66°F (19°C), with lows near 45°F (7°C). This is as mild as fall gets here, and you might still enjoy some comfortable days.
By October, highs drop to around 41°F (5°C), and lows get close to 26°F (-3°C). Freezing nights become the norm, and the first snow usually isn’t far behind.
In November, things really change. Highs only reach about 16°F (-9°C), and lows fall to around -2°F (-19°C). Daytime temps rarely climb above freezing at this point.
| Month | Avg. High | Avg. Low |
|---|---|---|
| September | 66°F / 19°C | 45°F / 7°C |
| October | 41°F / 5°C | 26°F / -3°C |
| November | 16°F / -9°C | -2°F / -19°C |
Daytime and Nighttime Temperature Swings
You’ll notice some big swings between day and night, especially early in the fall. In September, nights can be almost 20°F colder than daytime highs, so you might need a light jacket during the day and something warmer once the sun goes down.
By October, day and night temps get closer together, since both are dropping. In November, it’s cold all the time, so the difference between highs and lows isn’t as noticeable.
If you’re planning to be outside, these swings matter. Hiking or sightseeing in September might feel great during the day, but evenings can get chilly. By November, you’ll need heavy winter gear no matter what time it is.
Temperature Trends Compared to Other Seasons
Fall cools off way faster than spring warms up here. In just three months, average highs drop by nearly 50°F (27°C), and lows fall about 46°F (26°C). That’s one of the fastest transitions you’ll see all year.
Summer highs often reach the mid-70s°F (24°C), but fall quickly brings that winter feeling. For comparison, winter highs usually stay well below freezing, often between -12°F (-24°C) and 6°F (-14°C), so late fall really previews what’s coming.
Spring warms up more slowly, with snow sometimes lingering into April, while fall brings a much quicker slide into freezing weather. That rapid cooling is just a classic part of southern Siberia’s climate.
Cloud Cover and Sunshine During Fall
In Irkutsk, fall brings shorter days, more cloudy skies, and a steady drop in sunshine. These changes really shape how the season feels as it moves along.
Typical Cloudy Days
Cloud cover ramps up quickly through the fall. Early September gives you clear or partly cloudy skies about half the time, but by late November, overcast weather takes over almost two-thirds of the days.
You’ll notice the difference—a shift from those brighter early autumn days to much grayer skies later on. The cloudiest stretch usually lands at the end of November, with thick overcast skies showing up often.
Just to give you a sense:
- September: ~47% cloudy or overcast
- November: ~66% cloudy or overcast
So yeah, fall skies change fast around here.
Sunshine Hours in Autumn
Daylight hours drop quickly as fall goes on. At the start of September, you get more than 13 hours of daylight, but by the end of November, you’re down to a little over 8.
Shorter days and more clouds combine to cut down the sunshine you see. On average, Irkutsk gets about 254 hours of sunshine per month across the year, but autumn’s totals are way lower.
For example:
- September: Still a decent amount of sunshine thanks to longer days.
- October: Noticeable drop in daily sunlight.
- November: Not much daylight left, and clouds keep things even dimmer.
This steady fade really makes the season feel darker and colder, even before winter is officially here.
Impact of Cloudiness on Local Climate
More clouds affect both temperature and how comfortable you feel outside. Thick clouds block the sun, so afternoon highs drop faster than they do in early fall.
At night, those clouds trap a little heat, which keeps temperatures from falling as sharply as they might under clear skies.
If you’re visiting, expect cooler, dimmer days and not a lot of bright, sunny weather. Outdoor activities can feel less appealing, especially late in the season when daylight is short.
Cloudiness also marks the switch from rain to snow. By November, less sunlight and frequent overcast skies help the first lasting snow cover settle in. That’s when the growing season ends, and Siberia’s long winter really gets started.
Precipitation and Humidity in Autumn
During autumn in Irkutsk, rainfall drops off fast while snowfall gradually picks up. At the same time, humidity starts high but the air dries out as winter approaches.
Rainfall Patterns and Amounts
Rain falls sharply through the fall. Early September brings about 2.1 inches of rain in a 31-day stretch.
By late November, measurable rainfall is basically gone, since snow has started to take over.
The odds of a rainy day drop from about 27% in September to just 4% by late November. Instead, light snow starts showing up more, with average monthly snowfall reaching about 1.3 inches by season’s end.
So, if you’re traveling, you’ll want waterproof shoes in September, but by November, you’ll need warm, snow-ready gear.
Humidity Levels in Fall
Humidity stays pretty high during autumn—at least compared to other places this far north. In September, you’ll still notice some moisture in the air, but as it gets colder, the air can’t hold as much water.
By November, the air feels much drier, even though relative humidity numbers might look high. That’s just because cold air holds less moisture, so things feel crisp, not damp.
You won’t run into muggy weather here in the fall. Dew points stay low, and it’s basically impossible to feel sticky. The air feels cleaner, but it can dry out your skin, so you might want to keep some lotion handy.
Comparison with Other Seasons
Compared to summer, fall has way less rain. Summer brings lots of showers and the occasional thunderstorm, but autumn dries out quickly.
Winter barely gets any liquid precipitation—just snow. Spring is a bit wetter than fall, but it stays cool.
Fall stands out as the season when rain gives way to snow, and the air steadily dries out.
If you’re thinking about comfort, summer can feel damp thanks to higher humidity and rain, but fall usually brings clearer skies and drier air. That makes it a more predictable time for outdoor plans, though you’ll need to be ready for those sudden cold snaps.
Wind, Pressure, and Atmospheric Conditions
As fall moves in, Irkutsk’s weather shifts from mild to cold, and the air dries out as winter gets closer. Wind, air pressure, and visibility all affect how you’ll experience the season outdoors.
Prevailing Winds in Fall
Winds in Irkutsk during autumn usually stay light to moderate. Most days, you’ll notice average speeds around 4 mph, so strong gusts are rare this time of year.
The air feels much calmer than in spring, when wind speeds pick up noticeably.
Winds often blow in from the west or northwest. These directions bring in cooler air from Siberia, especially as autumn winds down.
They push out the leftover warmth from September, nudging temperatures lower through October and November.
Since the winds aren’t very strong, you won’t get the same harsh wind chill you’d feel in the open steppe.
Still, even a gentle breeze can sting a bit when it’s freezing at night. If you’re planning a walk along the Angara River or thinking about evenings outside, you’ll want a windproof jacket—it really helps.
Atmospheric Pressure Trends
Irkutsk sits pretty high up near Lake Baikal, and that changes how atmospheric pressure behaves. In fall, the average pressure sits around 719 mmHg (inHg equivalent), a bit higher than what you’d get in lowland places.
As autumn goes on, pressure tends to climb. September brings more ups and downs, sometimes dipping when rain rolls through.
By October and November, stable high-pressure systems take over, so you get colder, drier air.
These steady conditions clear up the skies in late fall. High pressure means fewer clouds, more sunshine, but also faster cooling once the sun goes down.
Visibility and Dew Point
Visibility in Irkutsk during fall usually stays pretty good, especially compared to the foggier spring months. Clear skies and steady air help you see for miles across the city and Lake Baikal.
If you visit in September or early October, you’ll probably get some of the best outdoor views.
The dew point drops as the season moves along. September might still feel a touch humid, but by late October, the air dries out a lot.
Lower dew points mean frost forms quickly overnight, especially on calm mornings.
This shift changes how comfortable you feel, too. Your skin and lips can dry out fast in the crisp air.
It’s smart to toss some moisturizer or lip balm in your bag if you’ll be outside a lot. With less humidity, you get clearer landscapes and sunsets—kind of a bonus, really.
Weather Forecast and Travel Planning
Fall in Irkutsk brings colder weather, shorter days, and a switch from rain to snow. Reliable forecasts, smart packing, and a good sense of timing make your trip a lot more comfortable.
Accessing Reliable Weather Forecasts
Weather in Irkutsk can change fast during fall. Temperatures drop from mild in early September to freezing by the end of November.
To keep up, you’ll want to check trusted sources for daily and longer-range forecasts.
Websites like Weather.com, Timeanddate.com, and Russian meteorological services update you on temperature, precipitation, and cloud cover.
As the season goes on, rain chances drop off and snow becomes more likely.
Keep an eye on daily highs and lows. Early September might still hit the mid-60s °F (around 18°C), but by late fall, daytime temperatures often stay below freezing.
Checking the forecast a few days before and during your trip helps you handle sudden cold snaps or early snow.
What to Pack for Fall Visits
What you pack depends on when you show up. Early fall feels cool, so light jackets and layers work well. By late fall, you’ll need heavier stuff for the cold.
Pack layered clothing—think thermal shirts, sweaters, and a windproof jacket. Temperatures can swing a lot between day and night, so layers let you adjust easily.
By October and November, add insulated coats, gloves, hats, and scarves to your list.
Footwear matters, too. Waterproof shoes or boots make sense since you could see rain in September and snow or icy sidewalks later.
A small umbrella is handy early in the season, but by November, snow gear works better.
Here’s a simple packing guide:
| Month | Clothing Focus | Extras |
|---|---|---|
| September | Light layers, jackets | Umbrella, comfortable shoes |
| October | Warm layers, heavier coat | Waterproof boots |
| November | Insulated coat, gloves, hat | Snow boots, scarf |
Best Times for Outdoor Activities
If you’re planning any outdoor activities in Irkutsk, timing really matters. September usually still brings comfortable weather, so you can stroll around, take day trips to Lake Baikal, or wander past the city’s old wooden buildings.
Early in the month, daylight sticks around for over 12 hours. That gives you plenty of time to enjoy being outside.
By October, temperatures drop fast. You can still get out for a hike or some sightseeing if you dress right.
Days get shorter and mornings feel colder, so it makes sense to start your plans earlier if you want to catch the light.
In November, things get rough. Freezing temperatures hit hard, and you only get about 8 hours of daylight.
If you visit then, try to keep outdoor trips short and spend more time indoors, maybe checking out museums or hanging out in local cafés to warm up.