What to pack for mid-June?

Question

I’m going on a Road Scholar tour next week (June 15-20) staying at the Lodge and have been checking the weather. Pretty well set with clothes for the hot sunny days. One evening I am doing the Night Sky walk, which basically involves relaxing on a canvas in a field for an hour or so at night. The tour also is taking us to the high country for one day; Tioaga Pass Road, Olmstead Point, Tenaya Lake, and Tuolomne Meadows. Weather forecast shows lows in the evening in the Valley in the 50’s, and highs in the days in the pass in the 60’s.

Will I want jeans and a hoodie or jacket? My other long pants would be lightweight convertible LLBeans. I will have a lightweight long sleeve shirt and a cotton cardigan. (And yes, I will have SPF 50 suntan lotion and 30% Deet wipes.)

Also the instructions recommend bringing a rain slicker but it seems very unlikely I would need it; looks like a standard suggestion. Good idea or not necessary?

Answer

Mid-June in Yosemite offers beautiful summer weather, but temperatures can swing dramatically between the warm valley floor and the cooler high country. Since you’ll experience both nighttime activities and higher elevations, packing with layers in mind is the right approach.

In Yosemite Valley, daytime highs will feel summery and warm, but evenings can drop into the low–mid 50s. Sitting still for over an hour during the Night Sky walk will make it feel colder than the number suggests. Up in the high country—Tioga Pass Road, Olmsted Point, Tenaya Lake, and Tuolumne Meadows—highs in the 60s can feel crisp, especially with wind or shade, and mornings can be quite chilly.

Because of the different climates you’ll encounter, you’ll be happiest if you have a reliable set of layers you can add and remove quickly. Your plan for lightweight shirts and a cardigan is good, but you will almost certainly want a warmer outer layer as well.

Bring a hoodie or light insulated jacket. Ideal for both the Night Sky program and windy moments in the high country.
Pack at least one pair of heavier pants like jeans. They’re perfect for cool evenings. Your lightweight convertible pants are great for daytime hikes but may feel too thin once the sun goes down.
Keep your long-sleeve shirt and cardigan. They stack well for temperature swings.
Pack a warm hat or light beanie. It makes sitting outside at night much more comfortable.
Bring sunscreen and insect repellent, which you already planned—excellent for both valley and high country.

As for rain protection, mid-June in Yosemite is typically dry, with thunderstorms being uncommon but not impossible at high elevations. While you may never use a rain slicker, carrying a very lightweight, packable rain jacket can be worthwhile.

If you already own a compact rain shell, bring it. It doubles as a wind layer in the high country and takes almost no space.
If you’d have to buy one specifically for this trip, it is reasonably safe to skip it, though having a wind-resistant layer is still a plus.
Ponchos are less useful in Yosemite’s typical summer winds; a light jacket is better if you choose to bring something.

Overall, plan for warm days, cool-to-chilly evenings, and significantly cooler temperatures at elevation. A hoodie, jeans, and a light rain/wind layer will cover every scenario you’re likely to encounter.

You’re very well prepared—just add one reliably warm top layer and you’ll be set for an excellent trip.