For the past week, the jet stream has forced Montana to resemble Arizona, prompting several fireworks and fishing restrictions.

High temperature records for the end of June have been blown out of the water in Montana, especially in the western part of the state. The heat settled over Washington, Idaho and Montana over the weekend, and temperatures 10 to 15 degrees above normal should last at least until Sunday.

On Saturday, records fell in Missoula, Kalispell and Butte, with temperatures 3 to 7 degrees above the previous mark. More records fell on Sunday as temperatures peaked in the triple digits.

The heat was the result of two trends related to climate change: higher temperatures in general and a big bulge in the jet stream.

Earth has experienced its warmest January through May period on record this year, and it is much easier to set all-time heat records when the baseline temperature is at record levels, according to meteorologist Jeff Masters.

Montana is normally isolated from southern influences by the jet stream passing overhead. However, this year, the jet stream has looped far to the north before swinging back down over the Dakotas. That’s allowed hot air from the Southwest to push up into Idaho and Montana.

The wandering jet stream is causing similar heat waves to occur over Western Europe.

Hot air heats the water, and temperatures in Montana’s rivers have reached dangerous levels for trout as streamflows continue to drop.

The lower Beaverhead, Jefferson, Gallatin and Flathead rivers are all running hot, exceeding 75 degrees on most days over the past week. Meanwhile, many streams are running far below their average levels for this time of year.

The preferred water temperature for rainbow and brown trout is about 56 degrees while native trout need even cooler water. Water temperatures of 77 degrees or more can be lethal to trout.

As of Friday, Montana Fish, Wildlife & Parks is instituting “hoot owl” restrictions on many streams in western Montana, including the Blackfoot, Clark Fork and Bitterroot rivers.

They should probably go into effect on other rivers in southwest Montana because the restrictions kick in when the water temperature hits 73 degrees or more for three days in a row. Fishing is allowed only between midnight to 2 p.m. to avoid stressing trout when the water temperatures are highest.

Normally, hoot-owl restrictions or fishing closures don’t occur until later in the summer but that can also be said about 100-degree days.

As the sun has scorched much of Montana, vegetation has become dangerously dry, and most Montanans know it won’t take much to spark wildfires.

Montana was lucky last year as much of the West burned around us. So far, that’s the case this year, with large fires in Oregon, Washington, Idaho and Colorado already burning, according to the National Interagency Fire Center.

Alaska is burning up with 21 wildfires after high temperatures there hit the 90s weeks before Montana.

But Montana’s first sizeable fire of the year, apart from a few small grassfires, is still burning along the North Fork of the Flathead River.

The Glacier Rim Fire about 12 miles north of Columbia Falls started on Saturday afternoon and has burned 85 acres as of July 1. Crews have put out all spot fires in nearby Glacier National Park and now have the Rim Fire 35 percent contained.

The fire continues to burn hot in the interior of the area because unseasonably warm weather and extremely dry fuel conditions are driving fire behavior into areas that were burned in a 2003 fire.

It is believed that the fire was human-caused. An investigation continues.

As July 4 nears, one of the most likely causes of wildfires would be fireworks. Fortunately, many counties and agencies are realizing the danger and are issuing fireworks bans prior to the Fourth.

Mineral, Missoula, Lake and Ravalli counties will all institute Stage 1 fire restrictions between Thursday and Friday. Over the next two days, Flathead and Silver-Bow counties will consider similar bans.

The cities of Missoula, Kalispell and several cities in the Bitterroot already have bans or will have by Friday. On Wednesday night, Butte was debating a ban.

The Confederated Salish and Kootenai Tribes have banned fireworks on the Flathead Reservation.

Fireworks are never allowed on state or federal public land.

However, fireworks stands remain open, increasing the likelihood of people using fireworks illegally.