About JP Weather Pro

What We Do

JP Weather Pro is a hyperlocal weather intelligence service for Japan's eight largest cities. We aggregate meteorological data from the Open-Meteo API — which incorporates Japan Meteorological Agency (JMA) Meso-Scale Model (MSM) and Global Spectral Model (GSM) outputs — and present it in a format optimized for practical decision-making. Current conditions, 24-hour temperature trajectories, 3-day forecasts, and utility guides for clothing and umbrella decisions.

We don't do everything. We don't provide 14-day forecasts (they're not reliable for local conditions). We don't include radar imagery or satellite loops. We don't have a mobile app (the website is responsive and loads faster than any app). We focus on what you need to decide what to wear, whether to carry an umbrella, and how to plan the next 24 hours.

The Team

Alex Park — Founder

Alex built JP Weather Pro in 2023 after three years of commuting in Tokyo's summer heat. He previously worked as a mobile application developer in Seoul and San Francisco before relocating to Tokyo. The direct motivation came from a July morning when he checked three different weather apps, all showing 29°C for Shinjuku, then stepped outside into conditions that felt like 38°C. The discrepancy between reported temperature and actual comfort was the final straw.

Alex handles the technical infrastructure, API integration, and site development. He's based in Shinjuku, Tokyo, and personally verifies the Tokyo weather data against JMA observations daily. You can reach him at jpweatherpro@jpweatherpro.com.

Mei Tanaka — Data Verification

Mei is responsible for checking API accuracy against JMA published observations. Every morning, she compares the previous day's forecasted temperatures and precipitation against what actually happened at JMA's AMeDAS stations across all eight cities. Discrepancies get logged. Patterns get analyzed. If Open-Meteo consistently overestimates summer temperatures in Nagoya by 2°C, we note it on the city page so users can calibrate.

Mei has a background in environmental science from Kyoto University and previously worked in climate data analysis at a research institute in Tsukuba. She joined JP Weather Pro because she was frustrated by weather apps that never acknowledged their own accuracy limitations. Her verification work is published on our accuracy log page.

Mei is based in Kyoto and covers the Kansai region (Osaka, Kobe, Kyoto-adjacent verification) in person. She also manages the Sapporo data verification remotely via JMA's online observation database.

Tom Wright — Content and Meteorological Writing

Tom writes the city weather guides and utility content. He has no formal meteorology training — he's a former journalist who covered energy policy and developed an interest in how weather affects infrastructure, energy demand, and daily life. His approach is explanatory: he researches meteorological phenomena and translates them into language that helps people make better decisions.

Tom's value is in connecting weather data to lived experience. He doesn't just report that Nagoya has high summer temperatures — he explains why the Nobi Plain traps heat, how the thunderstorm corridor forms, and what that means for someone walking from Nagoya Station to their office in Sakae. He's based in London and visits Japan 3-4 times per year for on-the-ground verification of his writing.

Why We Built This

The weather app market is dominated by global providers (Apple Weather, Google Weather, AccuWeather, Weather.com) that prioritize user engagement over information utility. Their apps include news feeds, video content, social features, and advertising. The weather data is buried under layers of content designed to maximize time-in-app and ad impressions.

We think this is backwards. Weather information is utility data. You need it quickly, accurately, and without distraction. A weather page should load in under 2 seconds, show you the numbers that matter, and get out of your way. That's what JP Weather Pro does.

The specific gaps we identified in existing services:

• No humidity-aware clothing guidance: Existing apps tell you the temperature but don't explain that 25°C in Osaka feels completely different from 25°C in Sapporo. Our "What to Wear" page fills this gap.
• No seasonal umbrella probability: Tourists and new residents don't know when to expect rain in Japan. Our "Umbrella Check" page provides monthly rain probability data that's specific to each city.
• No urban microclimate discussion: A single temperature for "Tokyo" is misleading. Our city pages explain why Shinjuku runs hotter than Odaiba, why Nagoya's basin traps heat, and why Kobe's Rokko Mountains create orographic rain.
• No accuracy transparency: Weather apps never tell you how accurate their forecasts are. We publish our accuracy log and explain the limitations of model data openly.

Our Approach to Data

We use the Open-Meteo Forecast API, a free, open-source weather data service that aggregates multiple numerical weather prediction models. For Japanese cities, the relevant model inputs are JMA's MSM (5km resolution, updates every 3 hours) and GSM (global, lower resolution). Open-Meteo blends these with ECMWF IFS model data to produce ensemble forecasts.

We don't manipulate the data. We don't add artificial "corrections." We don't smooth temperatures to make them look nicer. What you see on our dashboard is what the meteorological models output, translated into readable format. If the models are wrong, we note it in our accuracy log and explain why.

Our data updates every time you load the page. There's no caching that serves you stale information to save API costs. The timestamp at the bottom of each page shows exactly when the data was fetched.

Business Model

JP Weather Pro operates on a simple model. The website is free. We sell a PDF guide — "JP Weather Pro: Complete Seasonal Planning Guide" — for $12. The guide provides month-by-month weather breakdowns for all eight cities, detailed packing lists, seasonal activity recommendations, and historical weather statistics. It's designed for people planning extended stays, relocations, or frequent business travel to Japan.

We also offer a 30+ day full refund policy on the PDF guide. If it doesn't meet your needs, email us and we'll refund — no questions asked. Details are on our refund policy page.

We don't run ads. We don't sell user data. We don't have affiliate partnerships. The site exists because we think Japan weather information should be better than what global apps provide.

Legal Structure

JP Weather Pro LLC is registered in Nevada, USA. Our registered address is 300 S 4th St, Suite 1900, Las Vegas, NV 89101. We maintain a data desk in Tokyo at 2-11-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo 160-0023. For full business information, see our business information page.

We are not affiliated with the Japan Meteorological Agency. We are not a certified weather service. We are a data aggregation and presentation service. For official warnings (typhoons, tsunamis, severe weather), always consult JMA directly.

Contact

For data issues, city requests, corrections, or general feedback, use our contact form. For direct inquiries: jpweatherpro@jpweatherpro.com or call +1 (702) 483-6752 (USA) / +81 (3) 5321-8847 (Japan).