Climate Insights for Blenheim

The climate in Blenheim is temperate. The average annual temperature is 13°C and approximately 911mm of precipitation falls per year. Blenheim receives a notable amount of rainfall throughout the year, including during its driest month. Blenheim is in the Southern Hemisphere. The seasons are reversed: summer runs from December to February, while winter falls between June and August. The summer months are: January, February, December. The coldest months are July, August, June, when temperatures can drop to 6°C.

Blenheim sees moderate temperature variation throughout the year, ranging from 6°C to 21°C. January is the warmest month, though highs remain moderate at 21°C with a mean of 17°C. July is the coolest month, with minimum temperatures around 6°C and an average of 8°C. Daily temperature variation is modest, with an average difference of 7°C between highs and lows. The sharpest temperature change occurs between March and April, with a 2°C shift in average temperatures.

Blenheim is a moderately rainy area, receiving approximately 911mm of precipitation annually, which averages out to around 76mm per month. The wettest month is July, averaging 104mm of rainfall. December and June also tend to see above-average precipitation. The driest month is January, with just 56mm. That's 48mm less than July, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.

Blenheim is mildly breezy, with an average annual wind speed of 14km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is September, averaging 16km/h, though still comfortable for most outdoor activities. The calmest conditions occur in June, with average winds dropping to 13km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 3km/h between the calmest and windiest months.

It is currently spring in Blenheim, which began on September 23, 2026. Blenheim is in the Southern Hemisphere, where the seasons are reversed: spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in January at around 21°C, while the coldest stretch bottoms out in July near 6°C. Summer is next, beginning on December 21, 2026 (87 days from now).

The best time to visit Blenheim is during January, February, March and December, when the weather is most comfortable for travellers. During these months, average temperatures hover around 16°C with modest rainfall averaging 69mm per month. By contrast, July can be quite cold with temperatures dropping to 6°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Blenheim based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.