Allahabad is subject to a humid subtropical climate common to cities in the plains of North India, that is designated Aw under the Köppen climate classification. The annual mean temperature is 26.1 °C (79.0 °F); monthly mean temperatures are 18–29 °C (64–84 °F). Allahabad experiences three seasons: hot dry summer, cool dry winter and warm humid monsoon. Summer lasts from April to June with temperatures in the low 30s Celsius; during dry spells, maximum temperatures often exceed 40 °C (104 °F) in May and June. Monsoon begins in early July and lasts till September. Winter lasts from December to February. Temperatures rarely drop to the freezing point. Maximum temperatures are around 22 °C (72 °F) and minimum around 9 °C (48 °F). Allahabad also witnesses severe fog in January resulting in massive traffic and travel delays. It does not snow in Allahabad.
The highest recorded temperature is 48 °C (118.4 °F), and the lowest is −2 °C (28 °F).
Rains brought either by the Bay of Bengal branch of the south-west summer monsoon or by the Arabian Sea from the Arabian Sea branch lash Allahabad between June and September, supplying it with most of its annual rainfall of 1,027 mm (40 in). The highest monthly rainfall total, 296 mm (12 in), occurs in August. The month with the wettest weather is August when on balance 333 mm (13 in) of rain, sleet, hail or snow falls across 21 days; while driest weather is April when on balance 5 mm (0 in) of rain, sleet, hail or snow falls across 1 days. The city receives 2961 hours of sunshine per year, with maximum sunlight exposure occurring in
