Best time to go: month by month, for all five fly-in RV routes

In April, the sandstone in Zion is warm by mid-morning while Bryce Canyon, less than two hours' drive away and several thousand feet higher, can still get heavy spring snow [S1][S2][A]. In July, Phoenix averages 107 °F in the afternoon while the Grand Canyon's South Rim sits in the mid-80s [S1]. "When should we go?" has a different answer on every route, and sometimes on every night of the same trip.

This guide gives that answer for all five of our fly-in routes, month by month. Each route has a colour strip with our rating for every month, the average high temperatures that drive it, and the seasons that matter for an RV: when roads open, when campgrounds open, when shuttles run, and when the crowds come. Temperatures and dates come from NOAA climate normals, the National Park Service and Recreation.gov. The ratings themselves are our judgement, marked [A].

How we rate [A]: Best = comfortable temperatures, roads and campgrounds open. Good = fully doable with one drawback (heat, crowds, storms). Mixed = doable with real compromises. Tough = extreme heat or cold for RV life. Limited = key roads or campgrounds closed.

Las Vegas → Zion, Bryce & Grand Canyon

1. JanToughcold, Bryce snow
2. FebToughcold, Bryce snow
3. MarGoodZion shuttle starts
4. AprBestmild
5. MayBestwarm, busy
6. JunGoodhot in Zion
7. JulTough100 °F in Zion, storms
8. AugToughhot, monsoon
9. SepGoodstill hot early
10. OctBestmild, busy
11. NovGoodcold nights
12. DecToughcold, quiet

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• Sweet spots: April–May and October [A]. Zion averages 73–84 °F in those months, the South Rim 61–70 °F [S1].
• Summer: Zion averages 95–100 °F from June to August and Las Vegas over 100 °F [S1]. Bryce, much higher up, has highs in the high 70s to low 80s, with frequent afternoon thunderstorms and lightning in July and August [S2][A].
• Winter: Bryce falls below freezing nearly every night from October to May, and its coldest, snowiest months are December to February [S2]. Bryce's Sunset Campground and Zion's South Campground close for winter [S8].
• Crowds: Zion is busy from early February to late November; December and January are quieter, except holidays [S7]. The Zion Canyon shuttle runs daily from March through November, and private cars are not allowed on the Scenic Drive then [S7].
• Grand Canyon: busiest in spring break, summer and on fall and winter holiday weekends [S9].

Plan it: 10-day Las Vegas day-by-day · route guide · real cost

Salt Lake City → Arches, Canyonlands & Capitol Reef

1. JanToughcold, quiet
2. FebToughcold
3. MarGoodNeedles opens
4. AprBestmild, busy
5. MayBestwarm, busy
6. JunMixed93 °F
7. JulTough100 °F, 16 days over
8. AugToughmonsoon storms
9. SepGoodhot early, then mild
10. OctBestmild, busy
11. NovGoodcold nights
12. DecToughcold, quiet

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• Sweet spots: April–May and mid-September to October. NPS calls them the temperate and most popular seasons, with highs of 60–80 °F [S3].
• Summer: often over 100 °F; July averages 16 days above 100 at Arches. Late-summer monsoon storms can cause flash floods and close roads [S3]. Capitol Reef's monsoon usually runs July to September [S10].
• Winter: highs of 30–50 °F, lows of 0–20 °F; even a little snow or ice can make trails and roads impassable [S3]. Devils Garden becomes first-come, first-served from November to February [S11].
• Campgrounds: Devils Garden is reservable for nights March 1 – October 31, Needles Loop B from mid-March to mid-November, and Fruita all year [S11].

Plan it: 7-day Arches & Canyonlands day-by-day · route guide · real cost

Yellowstone & Grand Teton

1. JanLimitedroads closed
2. FebLimitedroads closed
3. MarLimitedroads closed
4. AprLimitedfirst roads open
5. MayMixedroads open in stages
6. JunBestall roads open
7. JulGoodbusiest
8. AugGoodbusiest
9. SepBestcooler, quieter
10. OctMixedroads close Oct 31
11. NovLimitedroads closed
12. DecLimitedroads closed

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• Sweet spots: June and September [A]. All park roads are open, campgrounds are open, and it's quieter than July–August [S5][S12][A].
• Roads (2026): the first roads open April 17 (West Entrance to Madison, Old Faithful, Norris, Mammoth and Canyon), then May 1, May 8 and Dunraven Pass on May 22; most close at the end of October. Only the road from the North Entrance to the Northeast Entrance stays open all winter [S5].
• Campgrounds (2026): Madison opened May 1 and Fishing Bridge RV Park May 8; Canyon not until May 29, Grant Village not until June 26. Most close in September or mid-October [S12].
• Weather: snow is possible in every month. Summer days are often around 70 °F, sometimes 80 °F, with afternoon thunderstorms; nights can drop below freezing up high [S13].
• Crowds: NPS warns that summer is busy, with lines at entrances, roadworks and wildlife jams [S14].

Plan it: 10-day Yellowstone & Grand Teton day-by-day · route guide · real cost

Denver → Rocky Mountain

1. JanLimitedeast side only
2. FebLimitedeast side only
3. MarLimitedeast side only
4. AprLimitedeast side only
5. MayMixedTrail Ridge opens ~late May
6. JunGoodsnow up high
7. JulGoodbusy, storms
8. AugGoodbusy, storms
9. SepBestquieter, crisp
10. OctMixedTrail Ridge closes
11. NovLimitedeast side only
12. DecLimitedeast side only

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• Sweet spots: late June to mid-September [A], when Trail Ridge Road is open. It is closed from about mid-October to late May [S6], and its average winter closure date is October 23 [S15].
• Timed entry (2026): May 22 – October 12 for the park, to October 18 for the Bear Lake Road corridor. That window is, in effect, the busy season [S16].
• Summer storms: afternoon thunderstorms and lightning are common in July and August, so start high-country days early [S17].
• Winter: only Moraine Park Campground stays open, first-come, first-served [S18]. The east side is still beautiful, but this route's crossing is closed [A].

Plan it: 6-day Rocky Mountain day-by-day · route guide · real cost

Phoenix → Sedona & Grand Canyon

1. JanMixedrim snow, freezing
2. FebMixedrim snow, freezing
3. MarGoodspring break crowds
4. AprBestmild
5. MayBestwarm in PHX
6. JunMixed104 °F in PHX
7. JulTough107 °F in PHX, storms
8. AugTough105 °F, monsoon
9. SepGood100 °F in PHX
10. OctBestmild
11. NovGoodcool, quiet
12. DecMixedrim snow

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• Sweet spots: April–May and October–November [A]. Phoenix is warm, not hot, and the South Rim averages 54–70 °F [S1].
• Summer: Phoenix averages 104–107 °F from June to August [S1]. Pickup day is the hard part; the rim itself is in the 80s [S4]. Thunderstorms with lightning are frequent in July, August and early September [S4].
• Winter: Phoenix is pleasant, but the rim gets snow, icy roads and lows in the teens °F [S4]. Hermit Road opens to private vehicles under 22 ft from December to February, with no shuttle [S19].
• Crowds: spring break, summer and fall weekends bring waits of up to two hours at the South Entrance between 10 am and 4 pm [S9]. Sedona's state-park campground is often sold out in spring and fall [S20].
• 2026: Stage 4 water restrictions at the South Rim; check the operations update for your dates [S21].

Plan it: 7-day Phoenix & Grand Canyon day-by-day · route guide · real cost

Choosing a route by month

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