The best months for this once in a lifetime adventure are during summer from December to April. In winter from June to August it can be extremely cold; the temperature of the water will be near freezing, and the water level is too high for caving. A wetsuit is already recommended in April. Hypothermia is an underestimated risk. The Broken River Cave is frequented during summer; be there either early or late in the day otherwise, you are queuing wet inside the cave instead of enjoying.
The powerful Broken River - The Cave Stream
Not advisable with a high water level. The deepest section is situated at the beginning of the cave adventure. If the water level is higher than your waist level, don't continue. It gets pretty cold, strenuous, and the water pressure is immense. Also, do not enter if it is raining; it can cause flooding! If the water of the river is not clear you also should not enter the cave. The most demanding obstacles at high water level are the second waterfall (1.50m high) and the last one at the end to reach the metal handles.
We did this cave twice once in February with a low water level easy to manage and in April with a higher water level. It was very challenging, we had to help each other, and although wearing a wetsuit it was pretty cold.
Weather Castle Hill
Precipitation occurs throughout the year. The wettest month is October and the driest February. The annual rainfall is roughly 1000 mm in comparison Arthurs Pass experiences about 4.500 mm a year. January is the warmest month but on average still below 20°C. Anyhow during summer temps around 25°C can happen. Almost freezing temps during winter.
Accommodations Close to Cave Stream
There are just two lodges next to the Cave Stream adventure. The Porters Lodge is situated in the mountains and has more a hostel character with an excellent restaurant. The other option is the Springfield Motel and Lodge. They offer well-equipped studios and rooms with shared facilities.
With over 1 million visitors each year, the amazing Postojna Caves are Slovenia’s most popular tourist attraction. Read our detailed tips about the best time to visit and how to avoid the crowds:
Avoiding Tourist Crowds
The tours are equally crowded throughout the year. The reason for this is the fact, that fewer tours being offered in offseason. Check the Postojna Caves Timetable. This usually results in the same long waiting lines at the ticket counter and equally large groups in the cave (up to 100 visitors per tour guide) regardless of the season. However, the months of late June until August are by far the most crowded ones. To enjoy a more pleasant and hassle free visit at any time, follow our tips:
It’s much better to buy your tickets online in advance: Online Tickets. Then you can skip the long waiting line at the ticket counter in the cave park. You still have to convert your ticket into a scannable barcode. However, there is a separate counter (Group/Online) for that with almost no people in the line. It saves you between 30 - 50 minutes of waiting in the standard ticket line. This also applies if you bought the ticket in advance at other places.
Book an Early Spot:
Book the first spot available at 9:00 AM (10:00 AM in the off-season). It’s much less busy at the entrance and in general. Later all the large tour buses arrive throughout the day. Additionally, the chances are at least slightly higher that you can join a smaller group in the cave with less than 100 visitors. (The English language groups are always the largest. Join another language group if you speak one of the other languages)
Arrive 30 Minutes Earlier:
If you bought tickets for the 9:00 AM slot, be at the Cave Park around 8:30. It takes up to 10 minutes to walk from the car park to the gates. You’ll also have time to use the restrooms and be the first in line for the electric train.You have to be there 10 minutes before your tour starts anyway
Another great option to getting away from the crowds are the Adventure Tours. These are always done in small groups (3-10 or 11-20). The price for the easiest tour is only 40 EUR, compared to 26 EUR for the regular visitor tour. Read more details about these tours in the description section below.
Regardless of the outside climate, the cave has a constant temperature of 8-10°C (46-50°F) throughout the year. However, you are probably planning more activities besides the cave. If you prefer pleasant temperatures visit between May and September (you might want to avoid the extreme tourist months of July and August for your Slovenia visit). Weather details (you can switch between °C and °F at the top): Postojna Weather Averages
Mammoth Cave National Park is a truly amazing year-round destination. Read our full season guide below and scroll down even further if you're interested in the best cave tours and the top tips before visiting almost at the end of this guide!
Special Tip: While you're in Kentucky, do not make the mistake and visit Mammoth Cave only. Take a look at Kentucky Off the Beaten Path® - A Guide to Unique Places. This guidebook from the 'Off the Beaten Path' series is terrific! It's your chance to visit unforgettable places!
In peak seasons (late spring until early fall) the cave draws big crowds, even more in the busy summer months. Each year, about 2 million visitors come to the park, with almost half a million of them taking a cave tour. Read our seasonal cave tour breakdown (shoulder season, high season, low season) and take a look at our tips to avoid the crowded tours in peak season. Please note that there are different tour schedules available for each season and that the number of participants allowed for each tour varies (up to 120). The visitation chart below contains official 2018 data. It gives you a nice insight about the busiest months at Mammoth Cave:
March - April - May | Spring (Crowded Tours): Early March is often still a good time crowd-wise. From mid-March until May the tours get more crowded, especially on weekends and public holidays (Memorial Day). Making online reservations is recommended. To ensure a slot for your desired tour, we suggest booking 1-2 weeks in advance, although for many tours it's sometimes possible to make reservations 1-3 days in advance only during the spring. Spring 2019 Schedule — March 10 - May 25
June - July - August | Summer (Very Crowded Tours): During peak summer months, the cave tours are heavily jammed. However, especially in June it's possible to get into a less crowded tour if you book an early morning spot on a weekday (Mon-Tue). Either way, making reservations is strongly recommended and often required to get into your desired tour. For the rare tours with very few participants, like the Wild Cave Tour, we highly recommend booking 3-4 weeks in advance, as it sells out real quick. Summer 2019 Schedule
September - October | Fall (Crowded Tours): After Labor Day weekend (early September) the crowds at the park thin out slightly at least, and not every tour is sold out in advance. However, it's still not quiet at all and making online reservations is recommended even during shoulder season.
November - February | Winter (Uncrowded Tours / Quiet Time): November and December are much quieter months. January and February is the quietest time in the park. During both months there is a possibility, that you may have a mid-week tour nearly to yourself. 'Walking along Broadway without anyone else is a surreal and otherworldly experience.' You'll also enjoy lowest hotel rates in winter. Winter 2018/19 Schedule
Avoiding Crowds and Waiting Lines
Since the cave temperature is at a constant 54 °F (12 °C) year-round, you may just visit in the off-season in winter (see above) or at least during shoulder months, in late fall or early spring. In the summer, the whole place is jammed with tourists, particularly between 10 a.m. and 2. p.m.
However, if you'd like to visit in the summer months or maybe you can only visit then, we got you covered. Choose from one or more of our 3 tips to dodge the crowded tours:
- Book the Earliest Tour Spot: Book one night at a close hotel (see the tips below the weather details). Then you use the NPS online reservation (click on the current schedule) and book the earliest tour spot before the buses arrive: 8:30 a.m., 8:45 a.m., 9:15 a.m. (depending on the tour). Book a few weeks ahead of time to make sure the slot is available. Additionally try to go mid-week (Mon-Tue) and not on the weekends. Even those early tours can still be crowded (full) at times but the whole park is a lot quieter in the morning without the masses of tourists arriving via buses.
- Book a Tour with Fewer Participants: The number of people allowed on a cave tour varies by tour. The 'Domes and Dripstones Tour' for example allows 118 participants, which results in quite a crowd when fully booked. The Frozen Niagara Tour allows 'only' 39 people. Combine this one with an early morning time slot (see above)! However, the best tour to avoid the crowds is the Wild Cave Tour: An intense and very strenuous 6 hour drive for spelunking enthusiasts. Up to 14 participants only.
- Use Another Parking Area: If you happen to arrive when everything is busy, do not use the parking lot in front of the Visitors Center. It's ridiculously crowded. Just park in the overflow parking at the Lodge (turn right before the Visitor Center). Walk through the Lodge and cross the bridge that takes you to the Center.
Weather (For Camping) | Cave Temperature
The cave has a constant temperature of 54 °F (12 °C) throughout the year, regardless of the outside weather. However, winter temperatures can be below freezing at entrances. In most areas of the cave, you'll be comfortable if you wear long pants and take a sweater or jacket with you.
Outside Weather: Even with the consistent year-round cave temperature, the outside weather shouldn't be overlooked. Not only by camping visitors (jump to the campsite section). In general, the climate around Mammoth Cave National Park is moderate with warm summers and pleasant spring and fall temperatures. Winters are mild and rarely harsh. Monthly climate details at Monthly Climate - Mammoth Cave. Excellent weather details including temperatures, rainfall, humidity and winds at Average Weather - Cave City Kentucky. For current conditions check out the weather webcam: Mammoth Cave NPS Webcam. Want to know the weather details for each season and month:
Spring Weather (March, April, May)
Spring is a pleasant time to visit the area, although the weather can vary a lot from day to day. In March the average highs already reach 61°F (16°C), in April 72°F (22°C). The nights are usually still chilly during March. In May it gets even warmer. May is also the month with the highest precipitation throughout the year. In general, rain is somewhat common during the spring with 8 to 9 days of precipitation per month. Also keep in mind that the weather is unpredictable, especially in spring. An afternoon can go from clear and sunny to rain or thunderstorms within two hours. Campgrounds open March 1 (see below). The campgrounds are not too busy in the spring (except for spring break and maybe weekends). Due to more precipitation, a rain fly is highly recommended for camping.
Summer Weather (June, July, August)
In general, the weather is quite stable compared to spring and other seasons. Summers outside Mammoth Cave are usually sunny, hot and humid. Daytime high temperatures often pass 90°F (32°C) in July and August. The downside is the high humidity between mid-June and mid-September. Especially from early July until mid-August / late August it gets really muggy, which might be uncomfortable for some visitors. On the other hand, the less humid and lower cave temperature comes in handy during those muggy summer weeks. If you're not bothered by the high humidity, the summer months are great for camping. Big plus: Thanks to the bats, you don't have to deal with mosquitoes at all.
Fall Weather (September, October, November)
Autumn weather can also be unpredictable, but not so much as in spring. In September it can still be humid, although not as muggy as in the summer months. The average highs reach 83°F (28°C). October is still pleasant with temps up to 72°F (22°C). In November it gets cooler but it's still mild with average highs of 60°F (15°C). Locals say that November weather can be nice most of the times. The campgrounds are significantly less crowded compared to summer. First signs of turning leaves are often in early October. And a good chance to catch the beautiful peak fall foliage colors is typically from mid to late October
Winter Weather (December, January, February)
Although it gets colder, the winter months are rarely harsh. However, ice storms in January and February are possible, which may cause difficult driving conditions. The snowy period usually starts early December and lasts until mid-March. Most snow falls in January and February. Although the cave temperature is constant year-round, it can be freezing in the cave entrance area in winter. In winter whole Mammoth Cave becomes a warm refuge and the quietness in the park area makes up for the lower outside temperature.
Summer months and dry weather are the best conditions to get about 150 meters deep inside of the cave. Not accessible in winter and after heavy rainfall.
All caves shouldn't be entered from October to mid-April. The caves are home for protected bats in the cold season.
The cave is closed from October until the end of March to protect the bats. It is advisable to visit the cave with dry weather conditions.
The cave is open from April to the end of September.
The cave is open daily from late April to late October at 9.20 a.m. and closing at 3.30 p.m. in 2017 from 29.04. until 10. June and 11.9. until 29.10. In summer from 11.06 until 10.9. the cave is open until 4 p.m.
The cave is located on 1.455-meter above sea level. Therefore, you are dependent on the cable car operating hours from Obertraun on 609-meter above sea level to Schönbergalm section I. The season for the cable car starts end of April and last until late October. The last mountain ascent is at 3 p.m. and in summer at 3.30 p.m. The last valley descent is shortly after 5 p.m. At poor weather conditions, the cable car might not run.
Check the opening hours first
A cave visit is a great option if the weather turns bad but expect more visitors having the same idea. It’s less crowded during nice weather when people think of outdoor activities.
Every year in August unique concerts are held in the Parsifal Dome.
Schedule about the offered concerts and booking.