The best time to visit Island Park, Idaho depends on your preferences and the activities you plan to engage in. BTW, here is the only weather forecast you will want to use – just click on the link to this page (click here) and then click National Weather Forecast. Google and the rest are usually so wrong it is comical but the National Weather Service is usually pretty accurate up here.

There is no best season to visit Island Park. July is the most popular season for sure and offers nice days and mild mornings but some folks love February for our deep snow and excellent snowmobiling. The best season depends on whether you like to float down crystal clear warm rivers in float tubes, fly fish the snake with late season grass hoppers, or enjoy the solitude of a quiet forest completely buried in snow. Here is my take on the seasons!

I’ve been around here for more than 40 years so let’s dig in and I’ll tell you what I’ve learned.

Mid July through Mid August are the hottest days. In general if you are here to swim in the lakes, boat, and/or float the rivers in inner tubes this is the ideal time to come. Huckleberries start getting ripe right around the start of August. Fishing is a little tougher during this period just because it can be in the mid-80s or low 90s. If you plan to fish we recommend getting up early. This time of year is also very crowded! After schools start after the 1st week of August and parents are getting ready for schools the crowds tend to drop by 30% (till Labor Day). Very few or no mosquitos but depending on the amount of rain late July can still have a few but usually very few.

Mid August till the end of Labor Day is a great time of year. It is less crowded except for Labor Day weekend. The water is just warm enough, the evenings are cool and there are no mosquitos! Fishing keeps getting better as we head towards fall and Yellowstone is starting to get a little less crowded. A few leaves even start to change colors but it is still feeling like Summer!

After Labor Day the traffic drops by about half (except for a little bump in fly fisherman who know the cooler air and diminished crowds make for excellent fishing). At this point int he year you will need to watch the weather if you plan on hiking or boating and expect cold mornings but nice days in the lows 70s and high 60s. Mid September through October is one of my favorite times of year. A lot of the tourists only show up on weekends. The forests get quite (except for hunters when the season opens) and the Fall colors can be spectacular in Island Park, as well as the fishing.

As we move into mid October winter is definitely in the air. There are still many nice days to be had before Thanksgiving but there will be frost in the morning and by Thanksgiving most of the aspen trees have lost their leaves. It is also not unusual to have a snowstorm or two leave a deep half foot of snow or more. This always melts sometime before mid December and there are many beautiful sweater days and fishing days mixed into the colder wintery days. Yellowstone National Park’s West entrance typically closes the first Monday of November at 9pm but can close earlier if deep snows fall. it usually doesn’t open again until the third Friday in April at 8am but this can vary as well. I can’t tell you how many people stop by our general store after the park roads are closed very disappointed they wont be able to enter the park. You can still always ski and depending on your plans, snowmobile (with a guide or reservation) in the Park but snowmobile tours need to be booked far in advance.

December varies. Watch the weather forecast (see link above for the only one I trust) and be as ready for snow as you are for rain. By mid December it is getting dark by 430pm and it is always starting to feel like winter. Usually by Christmas there is enough snow to snowmobile on trails and Christmas in Island Park is wonderful. The odds of not having a white Christmas are slim. Up until Christmas vacation this is a very quiet time in Island Park similar to mid to late November. Many places close down and don’t reopen until Christmas and some wait for the deeper snow and snowmobilers before reopening.

Late December through January is full on winter. The snow always piles up quickly and it is not unusual to get storms dumping 18 inches of snow. The depth quickly goes up and there are not many issues snowmobiling anywhere you want and Island Park has some of the best snowmobiling in the country. Generally, the snow starts to get really deep by the second week of January but it can easily start to pile up by New Years or even Christmas if there have been a couple of big winter storms. Usually there is not quite enough base to go too crazy off the trails but we have had winters where you can even this early. This time of year can also be VERY cold! Usually 20 degrees are the highs and lows can easily be in the negative 5 to negative 30 range at night. 4 wheel drive is of course recommended and Highway 20 usually closes a few times in the winter (at least for a few hours) as drifting snow blows across the highway.

Mid-January to Presidents day weekend is always a winter wonderland. Snowmobiles are in full force and Presidents Day can get crowded. All the local establishments have snowmobiles parked out front and this is a fun time of year if you are looking for a true winter experience. If you aren’t into snowmobiling there are plenty of other activities from ice fishing, to snowshoeing and cross-country skiing. Also of course the bears are hibernating so this is one of the times of year you don’t really need to worry about bear spray. Again, it is cold.

After President’s Day the winter recreation crowds drop off a bit but the snow just keeps getting deeper and the days longer through mid-March. This is probably one of the best times of year up here to play in the winter wonderland. Less crowds + deep snow! Many people are getting Spring fever and head to warmer places leaving the deep powder days of Island Park just waiting to be played in.

Late March and April can feel like Spring or deep winter. The days are getting longer and it is easy for a huge snowstorm to come in or you might just have a beautiful day. The graph below shows snow level and you can see that by the start of April old man winter starts to lose the battle and the snowpack starts to rapidly drop.

It is easy to see the level of snow drop 6 inches on a warm day in April! Of course a late storm can easily add that back but in general the snow pack drops rapidly after April. Because the snow is so deep even late April typically has a base similar to the base on New Years but the snow is definitely thicker and heavier. The bears are noticing the longer days as well and starting to wake up. A deep snowpack will mean still a lot of snow on the ground in April. A lite snowpack like we had in 2024 looks more like this:

Here is a picture of my cabin on March 27 during a lite snow year!

Here is a local road April 7th, notice the sun! A late winter storm could easily turn this into a powder day (although it would quickly melt):

By April 20th you can see the snowpack rapidly declining from the March picture above. Notice the strong shadows! The sun is getting stronger:

By May 1st it is really feeling like Spring but there are many patches of snow in the shade and forest service roads remain closed. There are not many people up here but there are many beautiful days and the small stout flowers start to appear by mid May along the banks of the Snake River in sunny patches. The snowpack melts very fast in May every year.

So we made it through winter! By Memorial Day most of the snow is gone but you might still find a few patches in the shade. Memorial Day is the first official day of crowds and after this weekend it gets a bit quiet again until the 15th of June when the green drake hatch starts and the Henry’s Fork opens to fly fishing. June is a wonderful month but can feel like winter, spring, or summer. There can be no very few mosquitos if the nights or cold or several days of lots of mosquitos (don’t worry it is never that bad). It varies greatly. After mid June the days start to get more consistently warm and long, the lakes are still a little cold, and mosquitos can still be present or not depending on how wet it has been and how warm the evenings are. Really the crowds start right before 4th of July weekend which is a great time of year up here (be sure to visit Lakeside Lodge’s annual firework show). After this scroll to the top of this article and begin the next year 🙂

In sum, every season is beautiful in its own way it really just depends what you are looking for!

Here is a breakdown of the weather and climate in Island Park throughout the year:

1. January: January is the coldest month in Island Park, with average high temperatures around 29°F (-2°C) and average low temperatures dropping to 7°F (-14°C). Expect snowfall and freezing conditions.

2. February: Similar to January, February remains cold with average high temperatures of 32°F (0°C) and average low temperatures of 10°F (-12°C). Snowfall is still common.

3. March: March brings a transition towards spring, but temperatures remain cool. Average high temperatures reach 40°F (4°C), while average low temperatures are around 17°F (-8°C). Snowfall is possible.

4. April: Spring brings milder temperatures to Island Park. Average high temperatures rise to 50°F (10°C), and average low temperatures hover around 26°F (-3°C). Snow is less common, but occasional rainfall can occur.

5. May: May shows further improvement in weather conditions. Average high temperatures reach 60°F (15°C), and average low temperatures are around 34°F (1°C). Spring foliage begins to emerge.

6. June: June marks the beginning of summer in Island Park. Average high temperatures climb to 71°F (22°C), and average low temperatures are around 40°F (4°C). It is a pleasant time to visit with longer daylight hours.

7. July: July is the warmest month in Island Park, with average high temperatures peaking at 80°F (27°C). Average low temperatures are around 46°F (8°C). It is a popular time for outdoor activities and exploring the area.

8. August: August continues to offer warm and pleasant weather. Average high temperatures remain around 78°F (26°C), and average low temperatures are around 44°F (7°C). It is a great time for hiking, fishing, and other outdoor adventures.

9. September: September brings the start of fall in Island Park. Average high temperatures drop to 67°F (19°C), and average low temperatures are around 35°F (2°C). Fall foliage begins to appear, creating beautiful scenery.

10. October: October sees cooler temperatures as autumn progresses. Average high temperatures reach 54°F (12°C), and average low temperatures drop to 26°F (-3°C). It is a quieter time to visit, with fewer crowds.

11. November: November brings colder temperatures and the possibility of snowfall. Average high temperatures are around 38°F (3°C), and average low temperatures drop to 16°F (-9°C). It is a good time for winter activities.

12. December: December is the beginning of winter in Island Park. Average high temperatures are around 29°F (-2°C), and average low temperatures drop to 8°F (-13°C). Snowfall is common, creating a winter wonderland.

It’s important to note that weather patterns can vary from year to year, so it’s always a good idea to check the local forecast before planning your trip to Island Park, Idaho.