Climate Report over Japan
Monthly Highlights
- Monthly mean temperatures were significantly above normal nationwide with the highest September records since 1946 in eastern/western Japan, as the whole country was covered by warm-air throughout the month, and affected by warm-air advection from the south in the middle of the month. The monthly anomaly of the average temperature over Japan was +2.66 ℃ (the warmest for September since 1898).
- Monthly precipitation amounts were above normal on the Sea of Japan side and the Pacific side of northern Japan, because these regions were well affected by fronts and low-pressure systems mainly in early to middle of the month. On the other hand, because the Pacific side of eastern and western Japan were less affected by fronts and low-pressure systems, monthly precipitation amounts were below normal on the Pacific side of eastern Japan and significantly below normal on the Pacific side of western Japan, and monthly sunshine durations were above normal in both regions.
- In Okinawa/Amami, monthly precipitation amounts were below normal and monthly sunshine durations were above normal, because the North Pacific subtropical High frequently covered the region.
Climate Anomaly Table Over Japan
Monthly Climate Anomaly over Japan
Time Series of Temperature Anomaly
Time Series of 10days Precipitation Amount Ratio and Sunshine Duration Ratio
10-day Mean Sea Level Pressure
10-day Mean 850hPa Temperature
10-day Mean 500hPa GeoPotential Height
10-day Mean Outgoing Longwave Radiation
Note: Figures of outgoing longwave radiation (OLR) in Monthly Report over Japan are based on the NOAA CPC Blended OLR data from the September 2023 report, while they were based on the NOAA CPC AVHRR OLR data until the August 2023 report.