Bihar, India · population 119,181 · 11 weather stations within 200 km · records 1814 to 2025
Siwan has an average annual daytime high of 31.0°C, based on the 1951 to 1980 baseline. Its warmest month is May, when highs typically reach 38.2°C, and its coldest is January, with overnight lows near 9.0°C.
These figures reflect annual averages, not single-day records. Daily observations are outside this dataset's precision.
Since 1900, Siwan's average temperature has risen by +1.2°C. Compared to the earliest station records that begin in 1814, warming totals +1.9°C.
20-year smoothed annual temperature reconstructed from station anomalies. Dashed line: 1951–1980 baseline.
Daytime highs sit within a comfortable 15°C to 26°C range.
Siwan's average annual daytime high is 31.0°C, based on the 1951 to 1980 baseline period. The warmest month is May, with highs averaging 38.2°C, and the coldest is January, with lows averaging 9.0°C.
May is the warmest month in Siwan, with typical daytime highs of 38.2°C.
2015 is the hottest year on record for Siwan, running +1.1°C above the 1951 to 1980 baseline.
Yes. Since 1900, Siwan has warmed by roughly +1.2°C.
January to December typically offers the most comfortable daytime highs, in the 15°C to 26°C range.
Baseline period 1951 to 1980. Monthly averages are the mean of station observations weighted by proximity. Warming trend is the 20-year smoothed anomaly against that baseline.