Thermal Buddy: Hiker's Logbook
Pack Right. Stay Warm.
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Start your yearly plan with a 1-month free trial. Log unlimited hikes, find your 'Just Right' layering, and stop packing on a guess.
Made for hikers, by a hiker.
Thermal Buddy was created by Eiji, a hiker and backpacker who learned the hard way that 'Light' isn't always 'Right.' After too many cold, sleepless nights under a tarp, he built this app to solve the layering guessing game once and for all. It is your private outdoor gear memory: a logbook that captures comfort, conditions, and kit so you stop repeating the same cold, sweaty mistakes.
STOP GUESSING. START PACKING 'RIGHT.'
In the backcountry, the right gear for the temperature is better than the lightest gear in your closet. Thermal Buddy helps you identify your personal 'Just Right' setup for any weather. Your comfort is unique; move beyond generic recommendations and rely on your own data.
— RECORD —
After your hike or run, log the temperature range, weather, wind, and the exact gear you wore and slept in. Split each outing into scenes — Active, Rest, Sleep, or Transit — and rate your comfort from Too Cold to Just Right to Too Hot.
— REFINE —
Create your personal database of what worked and what didn't in real conditions. The Search tab allows you to set a temperature range and instantly surface every past outing ranked by comfort. You’ll know exactly which base layer and shell combination worked last time conditions looked like this.
— ENJOY —
No more guessing. Use your data to dial in the Just Right layering and sleeping kit for your next adventure, so that you can just enjoy the outdoor experience.
BUILT FOR YEAR-ROUND ENTHUSIASTS
• Hiking, Trail Running, Backpacking, Mountaineering, Fastpacking, Road Running
• Log gear by brand, name, and category
• Track weather: sun, cloud, rain, snow
• Track wind: calm to strong
• Active, Rest, Sleep, and Transit scenes — with customizable names
• Temperature in °C or °F
• Filter by activity, weather, wind, and comfort rating
If you are a geek like me and want to know all the details, tap the 'App Support' link below to visit our site and read through the FAQ.
PRIVATE BY DESIGN
Your logbook lives on your device and syncs privately via iCloud. No account required. No servers. No ads. Anonymised usage signals are collected to improve the app — your personal logs are never shared.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Multi-day trips are here.
• Group related logs into a single trip — ideal for thru-hikes, hut-to-hut routes, and weekend backpacking. Each day is labelled automatically by date.
• Rename any day, remove a log from a trip, or add existing logs to a trip whenever you like.
Gear rows now show category icons across Record and Logbook, so your kit is easier to scan at a glance.
Japanese input, fixed.
• Editing notes with kana-to-kanji conversion is now smooth and reliable — no more dropped or scrambled characters. Long notes scroll cleanly, too.
Plus stability and polish throughout. Thanks for packing 'Right' with us!
The developer, Eiji Akiyama, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Purchases
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Eiji Akiyama
- Size
- 16.5 MB
- Category
- Sports
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Thermal Buddy Annual $9.99
- Thermal Buddy Lifetime $29.99
- Copyright
- © 2026 Eiji Akiyama (Thermal Buddy)