Climate Insights for Blenheim

The climate in Blenheim is temperate. The average annual temperature is 12°C and approximately 1094mm 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, March. The coldest months are July, August, June, when temperatures can drop to 5°C.

Blenheim sees moderate temperature variation throughout the year, ranging from 5°C to 22°C. January is the warmest month, though highs remain moderate at 22°C with a mean of 18°C. July is the coolest month, with minimum temperatures around 5°C and an average of 8°C. Daily temperature variation is modest, with an average difference of 8°C between highs and lows. The sharpest temperature change occurs between March and April, with a 3°C shift in average temperatures.

Blenheim is a moderately rainy area, receiving approximately 1094mm of precipitation annually, which averages out to around 91mm per month. The wettest month is November, averaging 117mm of rainfall. May and July also tend to see above-average precipitation. The driest month is February, with just 78mm. That's 39mm less than November, 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 relatively calm, with an average annual wind speed of 3km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is November, averaging 4km/h, though still comfortable for most outdoor activities. The calmest conditions occur in June, with average winds dropping to 3km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 1km/h between the calmest and windiest months.

It is currently winter in Blenheim, which began on June 21, 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 22°C, while the coldest stretch bottoms out in July near 5°C. Spring is next, beginning on September 23, 2026 — 93 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 17°C with modest rainfall averaging 86mm per month. By contrast, July can be quite cold with temperatures dropping to 5°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

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.