Summer in Irkutsk brings a blend of warmth, long daylight hours, and weather that can change on a dime. You’ll see average daytime highs between 22°C and 26°C (72°F to 79°F), which honestly makes this the best time to explore the city or wander around Lake Baikal.
Nights cool off, but not so much that you’ll skip an evening stroll or an outdoor dinner.
Rainfall peaks in summer, so you’ll want to keep an umbrella handy even when the sun’s out. The air feels fresh, thanks to moderate humidity. Extended daylight—over 16 hours in June and July—gives you all sorts of time for outdoor adventures.
This mix of gentle warmth, bright skies, and the occasional rain really sets the summer rhythm in Irkutsk. If you’re planning to sightsee or just soak up the seasonal vibe, knowing what the weather’s up to can make your trip a lot smoother.
Overview of Summer Weather in Irkutsk
Irkutsk’s summer brings mild to warm days and cool nights, plus regular rainfall. The season is short, but it’s definitely the most comfortable time to be here, with long days and a climate that really supports being outdoors.
Typical Summer Climate Patterns
In July, the warmest month, Irkutsk usually sees daytime highs between 70°F and 75°F (21°C–24°C). Nights get cooler, dropping to about 49°F (9°C), so you’ll want a light jacket once the sun goes down.
Rain visits often in summer. July brings about 60 mm (2.4 inches) of rain, and roughly one out of every three days sees some wet weather. Showers usually pass quickly, not those all-day drizzles.
Cloud cover hangs around, with skies partly to mostly cloudy about half the time. Still, daylight sticks around—midsummer days stretch nearly 17 hours. Winds stay gentle, around 6–7 mph, shifting from north in early summer to west by late August.
Humidity stays lower than in many places. You almost never get muggy days, so even the hottest afternoons feel pretty comfortable.
Comparison to Other Seasons
Summer stands in sharp contrast to the rest of the year in Irkutsk. Winters here are long, bitterly cold, and dry. January lows average -20°C (-4°F), and humidity can spike near 94%.
Snow falls often, and daylight can dip under 8 hours in midwinter.
Spring barely gets a moment—temperatures rise fast in May, and by late May, the growing season kicks off, lasting until mid-September. Autumn sweeps in quickly, with frost possible in early October, wrapping up the agricultural stretch.
Compared to these extremes, summer is really the only time you’ll see above-freezing temperatures day after day. It’s the warmest stretch of the year and also the rainiest, so the city feels alive with greenery and activity.
Weather in Irkutsk: Location and Climate Classification
Irkutsk sits in southeastern Siberia, not far from Lake Baikal, and sits at about 1,400 feet (430 meters) above sea level. Its spot far from the ocean brings wild swings between seasons.
The city’s climate goes under the humid continental with severe dry winters and warm summers (Dwb) label in the Köppen system. That means winters drag on and get harsh, while summers are short but not too intense.
On average, the year rounds out at about 2.5°C (36.6°F), with annual precipitation close to 500 mm (19.5 inches). Most of that rain falls in summer, while winters stay dry.
Because of its latitude and how far it is from the sea, Irkutsk sees daylight hours swing fast. Summer solstice brings nearly 17 hours of sun, but in winter, you get less than 8 hours. That really shapes how people live and what they do each season.
Average Summer Temperatures
Irkutsk’s summer brings mild to warm days and cool nights. July stays steadily warm, while June and August see more ups and downs, with evenings cooling off and hints of autumn sneaking in.
Daytime and Nighttime Temperature Ranges
During summer, daytime highs usually land between 70°F and 75°F (21°C–24°C). It’s rare for the mercury to climb past 85°F (29°C), so you probably won’t have to deal with sweltering heat.
At night, the temperature drops off. Lows average 49°F to 55°F (9°C–13°C). Early June can even dip near 35°F (2°C), so you’ll want to pack layers.
With warm afternoons and cool evenings, it’s smart to bring a light jacket. Even in July, you’ll probably need it after dark.
Monthly Temperature Breakdown: June, July, August
June kicks off the real warmth. Daytime highs average about 68°F (20°C), while nights hover near 48°F (9°C). Early June can still feel a bit like spring, but late June softens up.
July hits the peak. Highs average 73°F to 75°F (23°C–24°C), and lows stay around 54°F (12°C). This is when the weather feels most settled, with long days and not much chill.
August starts out warm but cools down as the month goes on. Highs drop to about 70°F (21°C), and lows head back toward 50°F (10°C). By late August, the days get shorter and evenings start to feel like fall.
Record Highs and Lows
Irkutsk has seen some temperature swings. The hottest summer days have reached about 85°F (29°C), but that’s not common—usually mid-July if it happens.
On the flip side, record lows for summer nights have dipped to around 35°F (2°C), especially in early June. That’s just Siberia’s continental climate at work, with big shifts from day to night.
Most visitors probably won’t run into these extremes, but it’s good to be ready for both warm afternoons and those surprise chilly nights.
Rainfall and Rainy Days in Summer
Rain ramps up in Irkutsk as summer goes on, with August standing out as the wettest month. Both the amount of rain and the number of rainy days climb as the season progresses.
Monthly Rainfall Totals
Rainfall in Irkutsk during summer shows a clear build-up from June to August. June gets about 71 mm, July jumps to around 85 mm, and August tops out at about 102 mm.
So, late summer feels a lot wetter than the start. If you’re planning to be outside, June is usually drier, but by August, showers are more frequent.
| Month | Average Rainfall (mm) |
|---|---|
| June | ~71 mm |
| July | ~85 mm |
| August | ~102 mm |
These numbers include rain and the occasional thunderstorm, which pop up most often in late July and August.
Frequency of Rainy Days
As the summer moves along, rainy days get more common. June averages about 10 to 11 rainy days, July ticks up to 12–13 days, and August leads with 14 rainy days.
By August, you’ll see rain nearly half the days in the month. Luckily, showers tend to be short-lived, so you still get plenty of clear spells.
If you’re traveling, bring light rain gear. Even though rain is frequent, it rarely ruins outdoor plans if you’re a bit flexible.
Typical Summer Precipitation Patterns
Irkutsk’s continental climate shapes how rain falls in summer. Passing low-pressure systems bring quick but sometimes heavy showers. Thunderstorms show up more in July and August, usually in the late afternoon or evening.
Rain spreads out across the month, not packed into just a few days. August tends to be the steadiest for wet weather, with both higher totals and more rainy days.
You’ll likely see sunny mornings that turn cloudy by afternoon. That makes early hours better for sightseeing, while later in the day, showers are more likely.
Humidity and Atmospheric Conditions
Summer in Irkutsk comes with moderate to high humidity, and it changes as the season goes on. These shifts affect how the warmth feels and how comfortable evenings are.
Average Relative Humidity Levels
During summer, relative humidity in Irkutsk usually sits between 55% and 72%. May is the driest, around 55%, but by June and July, humidity rises closer to 70%.
More rain means more moisture in the air. Even on mild days, higher humidity can make things feel a bit heavier.
At night, humidity often climbs higher than during the day. Evenings can feel cooler but also a touch damp. If you’re out after dark, you’ll probably notice it.
For visitors, it’s smart to pack light, breathable clothes. Planning breaks during the day, especially if you’re walking or hiking, also helps when humidity peaks.
Humidity Trends Throughout Summer
Humidity doesn’t stay steady all summer. Early June brings moderate levels, often in the 60% range, which feels comfortable. By July, humidity rises and often sits around 70% or higher.
More rain in July—averaging 90–100 mm—adds moisture, so some days feel hotter than the thermometer says.
By late August, humidity is still fairly high but starts to ease as rain lets up. Mornings might still feel damp, but afternoons lighten up a bit compared to July.
If you’re planning to be outside, expect stickier conditions in July and cooler, moist evenings in August. You can plan activities for the times of day that feel best.
Sunshine Hours and Daylight
Irkutsk gets a decent amount of sunshine during summer, with long daylight hours that help shape how you’ll spend your days. There’s a balance between direct sun and long days, so it feels bright but not overwhelming.
Average Daily Sunshine Hours
You’ll usually get 6 to 9 hours of direct sunshine per day in summer. May is often the sunniest, close to 8.9 hours daily, while July and August dip a bit but still bring steady brightness.
That’s enough to keep days lively without the harshness of more southern spots. Irkutsk’s yearly total is about 2,174 hours, which puts it somewhere between Chicago and London in terms of sun.
Clouds are part of the deal in Siberia. Rain in August, the rainiest month, can cut sunshine hours, but the long days still make outdoor time easy to find. If you’re into sightseeing or hiking, you’ll have reliable daylight and comfortable sun most days.
Day Length Variation in Summer
Day length stretches out in Irkutsk thanks to its northern spot. In June, the longest days last about 17 hours, with sunrise before 5:00 a.m. and sunset after 10:00 p.m.
By July, days shorten a bit to around 16 hours, and August drops to about 14.5 hours. Even then, evenings stay bright enough for late walks or activities.
This extra daylight means you don’t have to rush. You can explore Lake Baikal, stroll the city, or take day trips without watching the clock. The change in daylight is gradual, so you’ll adjust as summer heads toward fall.
Wind Speed and Weather Variability
Summer in Irkutsk brings moderate winds and shifting weather, and these changes really shape how you experience the outdoors. Temperatures usually stay mild, but wind speed and direction can change quickly, so they play a big role in comfort and planning.
Typical Summer Wind Speeds
In summer, winds in Irkutsk usually blow at 5 to 7 miles per hour. The windiest days show up in late spring and early summer, especially from mid-March to early June, when winds might pick up just a bit. By July and August, things settle down, and the air feels much calmer.
Most of the time, winds come from the west and northwest. The local landscape, including Lake Baikal, sometimes shifts the wind’s direction. You’ll notice that these breezes are more steady than gusty, which honestly makes planning your day a little easier.
Evenings usually bring lighter winds than midday. That’s pretty typical for continental climates, where the sun heats the ground and stirs up the air during the day. The winds aren’t strong enough to ruin your plans, but they add a cooling touch when summer temperatures climb.
| Month | Avg. Wind Speed (mph) | Conditions |
|---|---|---|
| June | 6.8 | Breezy, variable |
| July | 6.0 | Calmer, steady |
| August | 5.5 | Light, mild |
Impact of Wind on Comfort
Wind can really change how warm or cool you feel in Irkutsk. On days when highs reach the mid-70s°F (around 24°C), a steady breeze can make things feel cooler, especially if you’re in the shade or out in the open. That’s great for hikes or city walks, but if you’re near the water, it might actually feel a bit chilly.
Humidity stays pretty moderate in summer, so wind doesn’t crank up the discomfort like it does in tropical places. Instead, it helps balance out the warmth, making it easier to enjoy being outside.
If you’re planning to hang out along the Angara River or by Lake Baikal, expect stronger breezes in those spots. It can feel a few degrees cooler than downtown, even on sunny days. Tossing a light jacket or windbreaker in your bag is a good idea for those windier moments.
In July, when it gets both warm and humid, the wind brings some relief. Moving air cuts the heaviness of humid afternoons, and after a rain shower, the breeze helps clear the clouds. Sightseeing feels a lot more pleasant, even if the weather changes fast.
Travel Tips for Visiting Irkutsk in Summer
Irkutsk summers bring mild to warm days, cooler nights, and plenty of rain showers. You’ll get long daylight hours for sightseeing, but you should be ready for sudden weather shifts.
Best Activities During Summer Months
You can check out Lake Baikal, which is about an hour from Irkutsk. Summer feels like the perfect season for boat rides, hiking the shoreline, or visiting Olkhon Island. The water stays cold, but honestly, the views and the crisp air make up for it.
In town, you might wander through historic wooden houses or browse the central market. Outdoor cafes start opening in June, and you’ll find local dishes like omul fish from Baikal.
The Angara River embankment is a favorite spot for evening walks. You can hop on a short cruise too, and see the city from a different angle.
If you’re into nature, the East Sayan Mountains and Tunka Valley have great trails that aren’t too tough. You can get there by bus or on a tour from Irkutsk, and it’s usually cooler out there than in the city.
July and August bring festivals with music, crafts, and regional food. These events offer a fun way to experience Siberian traditions when the weather’s at its best.
Packing Recommendations for Summer Weather
Daytime highs in Irkutsk usually hit 20°C to 25°C (68°F to 77°F). Nights can feel chilly, dropping close to 10°C (50°F).
You’ll want to toss a light jacket or sweater into your bag for those cooler evenings. Trust me, it comes in handy.
Rain shows up pretty often in July and August. I suggest packing a waterproof jacket or just a small umbrella.
Shoes that can handle wet ground work better than sandals if you plan to explore on foot. No one likes soggy socks.
Pack layers, since the temperature might shift a lot between morning and afternoon. I usually go with a short-sleeve shirt under a light pullover, and it does the trick.
If you’re heading outdoors near Lake Baikal or the mountains, you’ll need sturdy walking shoes. Don’t forget insect repellent and sunscreen either.
Even when clouds hang around, UV rays hit harder at higher altitudes. That’s something people often underestimate.
Bring a daypack for your water, snacks, and rain gear. It just makes dealing with Irkutsk’s unpredictable summer weather way easier.