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Climate in Bryn Du · Met Office 1991–2020 averages

Bryn Du sits near the top of UK towns for mild winters

Peak summer warmth arrives in July, with afternoons near 19.0°C (66°F). Summers stay cool: July afternoons here are cooler than in 91% of UK towns. The year changes little: the coldest month’s nights and the warmest month’s afternoons are only 16°C apart. Homes need heating from November to April, the months averaging under 10°C.

July afternoons: cooler than 91% of UK towns
January nights: milder than 97% of UK towns
Rain a year: wetter than 79% of UK towns

Met Office 1991–2020 averages for the town itself.

A year in Bryn Du at a glance

Each month’s typical high and low, in °C.

Jan8°C3°C
Feb9°C3°CColdest nights
Mar10°C4°C
Apr12°C6°C
May15°C8°C
Jun17°C10°C
Jul19°C12°C
Aug19°C13°CWarmest
Sep18°C11°C
Oct15°C9°C
Nov now12°C7°CWettest
Dec9°C4°C
A normal year

What a year in Bryn Du feels like

Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.

Winter
9°C / 4°C
48°F / 39°F · 19 air frosts a year
Spring
13°C / 6°C
55°F / 43°F · 205 mm of rain
Summer
18°C / 12°C
65°F / 53°F · 3 days of 25°C+ a year
Autumn
15°C / 9°C
58°F / 48°F · 328 mm of rain, the wettest season
Best months to be outsideJunJulAugSepHighs of 17–27°C (63–81°F) and nights of 8°C (46°F) or more
Rain

About 1,024 mm of rain a year

November is the wettest month and June the driest. About 29 days a year bring 10 mm (0.4 in) or more.

1,024 mm
Rain a year (40 in)
Wetter than 79% of UK towns
29
Days a year with 10 mm of rain or more
1,575 hrs
Sunshine a year at Valley (Anglesey)
2.8 miles away

Rain by month

Millimetres

125 mm
JFMAMJJASOND

Sunshine by month

Hours of bright sunshine at Valley (Anglesey)

219 h
JFMAMJJASOND
Frost & warm days

19 air frosts and 3 days of 25°C a year

On about 19 nights a year the air drops below freezing; days that stay below freezing are rare. About 3 days a year reach 25°C (77°F).

19
Air frosts a year (below 0°C)
Fewer frosts than 96% of UK towns
under 1
Days that stay below 0°C
3
Days of 25°C (77°F) or more
Fewer warm days than 84% of UK towns

Day counts are 1991–2020 averages from the Met Office’s 2 km grid. The Met Office calls a day of 25°C or more a summer day and a night below 0°C an air frost; ground frosts, on grass, come more often.

Weather station

The Met Office station at Valley (Anglesey)

Valley (Anglesey) is 2.8 miles north-west of Bryn Du, 10 m (33 ft) above sea level. It is the nearest of the 37 long-running stations the Met Office publishes in full.

MonthHighLowRainAir frostsSun (hours)
January8.4°C3.8°C75 mm5.258
February8.4°C3.6°C62 mm4.881
March9.8°C4.5°C57 mm2.4126
April12.1°C6.1°C54 mm0.5173
May15.0°C8.6°C52 mm0.0219
June17.2°C11.0°C57 mm0.0203
July18.8°C12.9°C58 mm0.0190
August18.8°C13.1°C69 mm0.0176
September17.3°C11.6°C74 mm0.0143
October14.3°C9.2°C102 mm0.1101
November11.3°C6.6°C104 mm0.759
December9.1°C4.4°C94 mm4.246
Year13.4°C8.0°C857 mm181,575

Met Office historic station data, Valley, 1991–2020 months averaged (a month needs 20 of the 30 years; estimated values counted, missing months left out). Sunshine: Kipp & Zonen recorder.

Compared with other towns

How Bryn Du compares

Against the 2,537 towns and cities of 2,500 or more across the UK, each with its own Met Office averages, and its place among Gwynedd towns that size.

July afternoons19.0°C (66°F)
Cooler than 91% of UK towns
January nights3.5°C (38°F)
Milder than 97% of UK towns
Rain a year1,024 mm (40 in)
Wetter than 79% of UK towns
Air frosts a year19 nights
Fewer frosts than 96% of UK towns
Days of 25°C or more3 days
Fewer warm days than 84% of UK towns
Next door

Nearby towns’ climate

The nearest towns of 1,000+ within 12 miles: a hill, a valley or the sea can make a real difference over a few miles.

TownJuly highJanuary lowRain a year
Bryn Du19.0°C3.5°C1,024 mm
Bodedern 4.6 mi19.1°C about the same3.4°C about the same980 mm
Valley 5.3 mi19.0°C about the same3.8°C about the same893 mm
Llangefni 7.5 mi19.5°C about the same3.0°C 0.5°C colder1,148 mm
Llanerchymedd 8.4 mi18.4°C 0.6°C cooler3.1°C about the same1,087 mm
Holyhead 8.4 mi19.0°C about the same4.1°C 0.6°C milder872 mm
Gaerwen 8.6 mi19.7°C 0.6°C warmer3.0°C about the same1,142 mm
Month by month

Bryn Du weather by month

Average daily high and low, mean temperature and rain, 1991–2020, for the town itself (the Met Office’s HadUK-Grid).

MonthHighLowMeanRain
January8.4°C 47°F3.5°C 38°F6.0°C92 mm 3.6 in
February8.8°C 48°F3.5°C 38°F6.1°C73 mm 2.9 in
March10.1°C 50°F4.2°C 40°F7.2°C66 mm 2.6 in
April12.4°C 54°F5.7°C 42°F9.0°C65 mm 2.6 in
May15.2°C 59°F8.0°C 46°F11.6°C74 mm 2.9 in
June17.4°C 63°F10.4°C 51°F13.9°C65 mm 2.6 in
July19.0°C 66°F12.4°C 54°F15.7°C71 mm 2.8 in
August19.0°C 66°F12.6°C 55°F15.8°C82 mm 3.2 in
September17.5°C 64°F11.2°C 52°F14.4°C92 mm 3.6 in
October14.7°C 58°F9.0°C 48°F11.9°C112 mm 4.4 in
November11.7°C 53°F6.5°C 44°F9.1°C125 mm 4.9 in
December9.4°C 49°F4.4°C 40°F6.9°C107 mm 4.2 in
Year13.6°C7.6°C10.6°C1,024 mm
Sources

Where Bryn Du’s numbers come from

Averages over 30 years, not a forecast.

  • Mean temperature, rain and day counts: HadUK-Grid 1991–2020 averages for the Met Office 2 km grid square nearest Bryn Du’s centre (the town is smaller than one square).
  • Highs and lows: the Met Office publishes average daily maxima and minima on its 12 km grid; each is moved by the difference between the town’s 2 km mean temperature and the 12 km square’s, which carries the town’s own height and setting over.
  • Weather station and sunshine: Met Office historic station data for Valley, 2.8 miles away, months of 1991–2020 averaged.
  • Comparisons: every town and city of 2,500 or more across the UK, all four nations, read the same way.

Met Office HadUK-Grid · Met Office Climate Data Portal · Historic station data. Open Government Licence v3.0.

Questions about Bryn Du’s climate

How warm does Bryn Du get in summer?

August is the warmest month, with average highs of 19.0°C (66°F). About 3 days a year reach 25°C (77°F), fewer than 84% of UK towns.

How cold does Bryn Du get in winter?

February nights average 3.5°C (38°F). The air drops below freezing on about 19 nights a year, and about under 1 days a year stay below freezing all day.

How much rain does Bryn Du get?

About 1,024 mm (40 in) a year, more than 79% of UK towns. November is the wettest month (125 mm) and June the driest (65 mm).

How sunny is it?

The nearest Met Office station with a sunshine record, Valley (Anglesey) (2.8 miles away), averages 1,575 hours of bright sunshine a year. Sunshine isn’t on the town grid, so this is the station’s figure.

Where do these figures come from?

The Met Office’s HadUK-Grid 1991–2020 averages, which turn thousands of weather stations into a map of the UK in 2 km squares; the page reads the squares inside Bryn Du. They are 30-year averages, not a forecast.

Contains Met Office data © Crown copyright 2026, Open Government Licence v3.0. HadUK-Grid 1991–2020 averages via the Met Office Climate Data Portal; station averages from Met Office historic station data. Today’s forecast for Bryn Du →

Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.