Is the Summer of 2025 Really Abnormal? Comparing Temperature, Humidity, and Experience with 2024
“Isn’t this summer dangerous?” ── The truth behind that uneasy feeling
“It feels much hotter than last year.”
“It never cools down at night.”
Many people in 2025 may be saying exactly this.
But how different is this summer compared to 2024, really?
Based on official data from the Japan Meteorological Agency, let’s thoroughly compare the summer of 2024 and 2025 and uncover why this year feels so abnormal.
📊 Temperature Comparison (2024 vs. 2025)
2024 (Osaka)
- Extreme heat days (above 35°C): 6 days
- Tropical nights (above 25°C): 12 days
2025 (Osaka, June–July)
- Extreme heat days (above 35°C): 13 days
- Tropical nights (above 25°C): 24 days
👉 Both extreme heat days and tropical nights doubled.
No wonder sleep is harder to come by this year.
Related: Are Tropical Nights Increasing Year by Year? Osaka Data Analysis
💧 Humidity Anomalies: The Silent Stress Factor
Temperature isn’t the only culprit. Humidity also plays a massive role.
Average Relative Humidity (Osaka, July)
-
2024
- Average: 72%
- Days over 80%: 9
-
2025
- Average: 79%
- Days over 80%: 17
High humidity prevents sweat from evaporating, which means your body can’t cool down.
Result: constant stickiness and the feeling that “it’s not cooling down even with wind.”
Related: Why Humidity Makes Summer Fatigue Worse
🧠 The Difference Between “Heat on Paper” and “Heat You Feel”
Heat is more than just numbers on a thermometer.
Indexes like WBGT (heat index) and perceived temperature combine factors like humidity, wind, and solar radiation.
In 2025, these indicators reached the worst levels of the past five years:
- Higher risk of indoor heatstroke
- Fans no longer sufficient
- Even air conditioning struggles at night
This lingering “body heat” is what makes this summer feel so relentless.
🧊 Survival Tips: Cooling the “Brain” Too
Recent research shows that brain temperature strongly affects concentration and mood.
Even if your room is cool, your brain may still be overheated.
Practical countermeasures:
- Cool the back of your head with a towel
- Use an ice pillow or gel pillow before bed
- Take short breaks and move to refresh during work
👉 Related: “Hot Brain” Summer—Why You Can’t Concentrate
✅ Summary: The Triple Punch of Summer 2025
- Extreme heat days and tropical nights doubled compared to 2024
- Humidity magnified the sense of fatigue and heat stress
- More than “just hot”—this year’s discomfort doesn’t go away
To get through this abnormal summer, it’s not enough to rely only on air conditioning.
Managing humidity and cooling your brain are key to survival.
“It’s only mid-August.”
Let’s stay cautious and protect ourselves for the weeks ahead.