Blenheim weather in December

In December, Blenheim sees average daytime highs of 19°C and overnight lows near 12°C, with 73 mm of rain across 10.4 wet days and about 14.9 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs climb over the month, from about 18°C in the first days to 19°C by the end. The sky is clear or mostly clear about 26% of the time in December, and the air most often feels dry.

Daylight stretches from about 14 h 48 min at the start of December to 15 hours by month's end. Set against the rest of the year, December is Blenheim's 12th-clearest and 3rd-windiest month. For the whole year in context, see Blenheim's year-round climate.

Daytime high
19°
4th warmest
Overnight low
12°
10th coldest
Rainfall
73 mm
10.4 wet days
Daylight
15 hours
5:51 AM – 8:50 PM
Cloud cover
62%
12th clearest
Wind
15 km/h
3rd windiest
Solar energy
7.04 kWh/m²
Travel score
6.0
out of 10

Blenheim is town in New Zealand.

Air quality
Good
PM10 18.5 µg/m³ · 2012
Density
287/km²
people per km²
Founded
1850

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 18°C in the first days to 19°C by the end.

A typical December day in Blenheim reaches about 19°C in the afternoon and slips back to 12°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 22°C. Set against its neighbours, December runs about 2°C warmer than November and about 2°C cooler than January.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
11811
21811
31811
41811
51811
61811
71811
81811
91811
101811
111811
121811
131812
141912
151912
161912
171912
181912
191912
201912
211912
221912
231912
241912
251912
261912
271912
281912
291912
302012
312012

Blenheim weather by month

How December compares with the rest of the year at a glance. December is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan20° / 13°608.114.76.6
Feb20° / 13°536.313.76.9
Mar19° / 11°537.112.36.6
Apr16° / 678.210.95.5
May14° / 638.49.74.4
Jun12° / 819.49.13.1
Jul11° / 769.79.32.7
Aug12° / 7410.810.33.1
Sep13° / 7310.311.73.8
Oct15° / 8311.113.14.6
Nov17° / 10°739.914.35.4
Dec19° / 12°7310.414.96.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in December, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 18% of December, with mostly cloudy or overcast conditions the remaining 56%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
24159
34060
44159
54159
64159
74159
84258
94258
104258
114357
124357
134258
144357
154357
164357
174456
184555
194555
204555
214555
224654
234654
244654
254654
264753
274753
284753
294951
304951
314951

Chance of precipitation in December

Any precipitation

Blenheim gets around 73 mm of rain over 10.4 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 34% and peaks near 35% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
134
234
334
434
534
634
734
834
934
1034
1134
1234
1334
1434
1535
1635
1735
1835
1935
2035
2134
2234
2334
2433
2533
2632
2732
2831
2931
3030
3130

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the dry band about 77% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
185141
284151
383161
482171
581181
680191
779201
879201
978211
1078211
1177221
1277221
1377221
1477221
1576222
1676222
1776222
1876222
1976222
2075232
2175232
2275232
2375232
2474242
2574242
2674242
2774242
2872253
2972253
3071263
3171263

Wind in December

Winds average 15 km/h in December.

Across December, daily wind ranges from about 15 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
116light breeze
216light breeze
316light breeze
416light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2516light breeze
2616light breeze
2716light breeze
2816light breeze
2916light breeze
3016light breeze
3116light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 14 h 48 min at the start of December to 15 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over December. Sunrise moves from 5:50 AM to 5:58 AM, and sunset from 8:37 PM to 8:56 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.85:508:37
214.85:508:38
314.85:508:39
414.85:508:40
514.95:508:41
614.95:508:42
714.95:508:43
814.95:508:44
914.95:508:45
1014.95:508:46
1114.95:508:46
1215.05:508:47
1315.05:508:48
1415.05:508:49
1515.05:508:49
1615.05:518:50
1715.05:518:51
1815.05:518:51
1915.05:528:52
2015.05:528:52
2115.05:528:53
2215.05:538:53
2315.05:538:54
2415.05:548:54
2515.05:548:55
2615.05:558:55
2715.05:568:55
2815.05:568:56
2915.05:578:56
3015.05:588:56
3115.05:588:56

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 7.04 kWh/m².

For context, solar energy here swings from a low near 1.7 kWh/m² to a high of 7.31 kWh/m² in January across the year — December's 7.04 kWh/m² sits near the top of that range.

02468151015202531
Solar energy (kWh/m²)Level
16.8Intense
26.8Intense
36.8Intense
46.8Intense
56.8Intense
66.9Intense
76.9Intense
86.9Intense
96.9Intense
106.9Intense
116.9Intense
127.0Intense
137.0Intense
147.0Intense
157.0Intense
167.1Intense
177.1Intense
187.2Intense
197.2Intense
207.2Intense
217.3Intense
227.3Intense
237.4Intense
247.4Intense
257.5Intense
267.5Intense
277.6Intense
287.6Intense
297.7Intense
307.7Intense
317.7Intense
Planning a trip in December

Is December a good time to visit Blenheim?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.0
Sightseeing
4th-best month of the year
2.4
Beach & pool
4th-best month of the year

December is a reasonable time to visit Blenheim for sightseeing.

What to pack for Blenheim in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Blenheim sees daytime highs around 19°C and nights near 12°C. Pack sun protection. Worth having: rain gear. About 10 days see rain.

sun protectionrain gear

Sea temperature near Blenheim in December

The nearest coast averages about 15°C in December — 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.

10°12°14°16°18°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan16Cool
Feb17Cool
Mar16Cool
Apr15Cool
May14Bracing
Jun13Bracing
Jul12Bracing
Aug12Bracing
Sep12Bracing
Oct13Bracing
Nov14Bracing
Dec15Bracing

UV index in Blenheim in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeModerateLowModerateHighVery highExtremeJan 11UV 11Jun 16UV 1
UV index (midday)Level
Jan11Extreme
Feb10Extreme
Mar6High
Apr4Moderate
May2Low
Jun1Low
Jul2Low
Aug3Moderate
Sep4Moderate
Oct6High
Nov9Very high
Dec11Extreme
Location & terrain

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.

3 km
79 m
16 km
899 m
80 km
2,829 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland
December weather nearby: Picton 25 km · Nelson 62 km · Stoke 64 km · Richmond 67 km · Karori 71 km · Wellington 73 km · Porirua 86 km · Lower Hutt 87 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
no religion 49%Christian 37%objected to answering 7%Hindu 3%

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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).