2026【群馬県】 真夏に涼しい峠道ベスト10（前編）気象庁データから8月の平均気温を計算！夏のツーリング、ドライブの参考に！

This is the first part of our "Top 10 Coolest Mountain Passes in Gunma Prefecture in Midsummer (2026 Edition)" (Ranked 10th to 6th). We investigated high-altitude mountain passes accessible by car and motorcycle from Gunma Prefecture and ranked the roads that are relatively cool even in midsummer. This ranking was determined using the following unique rules: Only mountain passes within Gunma Prefecture and those on the border with Gunma Prefecture are included. Dead-end (end-and-back) mountain passes are included. Only paved roads directly accessible from the Gunma Prefecture side are included. Unpaved roads and roads with private vehicle restrictions are not included. Mountain passes that can actually be driven on by car or motorcycle. The same road or high-altitude spots in almost the same location are not duplicated. The average temperature for each road was calculated using the following standard: Average temperature for August 2025 at the Japan Meteorological Agency's Kusatsu Observatory (altitude 1,223m): 21.4℃ The temperature change is calculated using a general temperature lapse rate of approximately 0.6℃ per 100m of altitude. *Temperatures are estimated values. For each mountain pass, we also introduce: Elevation Estimated average temperature for August 2025 Road conditions Scenery Tourist spots and event dates Recommended touring/driving routes The roads introduced this time (10th to 6th place) Tenjin Pass (Mt. Haruna) Jikkoku Pass Torii Pass (Tsumagoi Village) Hachijo Pass (Mt. Akagi) Budou Pass #Gunma Prefecture #Touring #Driving #Mountain Pass #Ranking #Cool