Blenheim in Summer
In summer (December, January and February), Blenheim sees average daytime highs around 20°C and overnight lows near 12°C, with 186 mm of rain over about 25 wet days across the season. It is the warmest season of the year and the 3rd-wettest season.
Over the season highs climb from about 18°C in early December to 20°C by late February. The sky is clear or mostly clear about 32% of the time across summer, and the air most often feels dry.
Summer is Blenheim's best season of the year to visit on our travel score. For the whole year in context, see Blenheim's year-round climate.
- Avg daytime high
- 20°C
- warmest season of the year
- Avg overnight low
- 12°C
- Rainfall
- 186 mm
- 25 wet days
- Avg wind
- 15 km/h
- Travel score
- 6.5
- best season of the year
- Months
- Dec · Jan · Feb
Temperature in Blenheim in Summer
Over the season highs climb from about 18°C in early December to 20°C by late February.
A typical summer day in Blenheim reaches about 20°C and drops to 12°C overnight. The warmest of the three months is February, the coolest December.
Blenheim weather by month
How the three summer months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 20° / 13° | 60 | 8.1 | 14.7 | 6.6 |
| Feb | 20° / 13° | 53 | 6.3 | 13.7 | 6.9 |
| Mar | 19° / 11° | 53 | 7.1 | 12.3 | 6.6 |
| Apr | 16° / 9° | 67 | 8.2 | 10.9 | 5.5 |
| May | 14° / 7° | 63 | 8.4 | 9.7 | 4.4 |
| Jun | 12° / 5° | 81 | 9.4 | 9.1 | 3.1 |
| Jul | 11° / 5° | 76 | 9.7 | 9.3 | 2.7 |
| Aug | 12° / 5° | 74 | 10.8 | 10.3 | 3.1 |
| Sep | 13° / 7° | 73 | 10.3 | 11.7 | 3.8 |
| Oct | 15° / 8° | 83 | 11.1 | 13.1 | 4.6 |
| Nov | 17° / 10° | 73 | 9.9 | 14.3 | 5.4 |
| Dec | 19° / 12° | 73 | 10.4 | 14.9 | 6.0 |
Cloud cover in Summer
The sky is clear or mostly clear about 32% of the time across summer.
Chance of precipitation in Summer
Blenheim gets around 186 mm of rain over 25 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 15 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 48 min in early December to 13 h 06 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 6.8 kWh/m².
Is summer a good time to visit Blenheim?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Blenheim for sightseeing.
What to pack for Blenheim in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Blenheim sees daytime highs around 20°C and nights near 12°C. Pack sun protection. Worth having: rain gear. About 25 days see rain.
Sea temperature near Blenheim in Summer
The nearest coast averages about 16°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 21 km away) is warmest in February at about 17°C and coldest in August near 12°C.
The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 16 | 17 | 16 | 15 | 14 | 13 | 12 | 12 | 12 | 13 | 14 | 15 |
| Comfort | Cool | Cool | Cool | Cool | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 16 | Cool |
| Feb | 17 | Cool |
| Mar | 16 | Cool |
| Apr | 15 | Cool |
| May | 14 | Bracing |
| Jun | 13 | Bracing |
| Jul | 12 | Bracing |
| Aug | 12 | Bracing |
| Sep | 12 | Bracing |
| Oct | 13 | Bracing |
| Nov | 14 | Bracing |
| Dec | 15 | Bracing |
UV index in Blenheim in Summer
Clear-sky midday UV across summer averages around 11 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Blenheim peaks around January 11 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 16 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 11 | 10 | 6 | 4 | 2 | 1 | 2 | 3 | 4 | 6 | 9 | 11 |
| Level | Extreme | Extreme | High | Moderate | Low | Low | Low | Moderate | Moderate | High | Very high | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 11 | Extreme |
| Feb | 10 | Extreme |
| Mar | 6 | High |
| Apr | 4 | Moderate |
| May | 2 | Low |
| Jun | 1 | Low |
| Jul | 2 | Low |
| Aug | 3 | Moderate |
| Sep | 4 | Moderate |
| Oct | 6 | High |
| Nov | 9 | Very high |
| Dec | 11 | Extreme |
Where is Blenheim?
Blenheim sits at 41.5°S, 174.0°E, 9 m above sea level, in New Zealand. The nearest listed city is Picton, 25 km away.
Topography around Blenheim
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Blenheim.
Within 3 km, the terrain around Blenheim has only modest variations in elevation — a maximum elevation change of 79 m around an average of 9 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 899 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,829 m.
The land around Blenheim is covered by grassland (47%) and artificial surfaces (32%) within 3 km, grassland (53%) and trees (24%) within 16 km, and water (47%), trees (28%) and grassland (21%) within 80 km.
New Zealand travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type I
- 230 V · 50 Hz
- Prices
- ≈ 86% of US
- price level, 2025
- GDP per capita
- $49,591
- 2025
- Happiness
- 7.0 / 10
- World Happiness, 2025
- Safe drinking water
- 100%
- of population, 2024
- Homicide rate
- 1.5
- per 100k, 2022
- Road deaths
- 9.6
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Blenheim (-41.516°, 173.9528°, elevation 9 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.