Penysarn has some of the coolest summers among UK towns
The coldest hours of a January night bottom out at 3.3°C (38°F) on average. The seasons sit close together: from a winter night to a summer afternoon the average spans only 15°C. Frosty nights are scarcer than in 98% of UK towns. If you like long walks, July and August offer highs of 18°C.
Met Office 1991–2020 averages for the town itself.
A year in Penysarn at a glance
Each month’s typical high and low, in °C.
What a year in Penysarn feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,066 mm of rain a year
October is the wettest month and April the driest. About 34 days a year bring 10 mm (0.4 in) or more.
Rain by month
Millimetres
Sunshine by month
Hours of bright sunshine at Valley (Anglesey)
14 air frosts and 1 days of 25°C a year
On about 14 nights a year the air drops below freezing; days that stay below freezing are rare. About 1 days a year reach 25°C (77°F).
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.
The Met Office station at Valley (Anglesey)
Valley (Anglesey) is 13 miles south-west of Penysarn, 10 m (33 ft) above sea level. It is the nearest of the 37 long-running stations the Met Office publishes in full.
| Month | High | Low | Rain | Air frosts | Sun (hours) |
|---|---|---|---|---|---|
| January | 8.4°C | 3.8°C | 75 mm | 5.2 | 58 |
| February | 8.4°C | 3.6°C | 62 mm | 4.8 | 81 |
| March | 9.8°C | 4.5°C | 57 mm | 2.4 | 126 |
| April | 12.1°C | 6.1°C | 54 mm | 0.5 | 173 |
| May | 15.0°C | 8.6°C | 52 mm | 0.0 | 219 |
| June | 17.2°C | 11.0°C | 57 mm | 0.0 | 203 |
| July | 18.8°C | 12.9°C | 58 mm | 0.0 | 190 |
| August | 18.8°C | 13.1°C | 69 mm | 0.0 | 176 |
| September | 17.3°C | 11.6°C | 74 mm | 0.0 | 143 |
| October | 14.3°C | 9.2°C | 102 mm | 0.1 | 101 |
| November | 11.3°C | 6.6°C | 104 mm | 0.7 | 59 |
| December | 9.1°C | 4.4°C | 94 mm | 4.2 | 46 |
| Year | 13.4°C | 8.0°C | 857 mm | 18 | 1,575 |
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.
How Penysarn 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.
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.
| Town | July high | January low | Rain a year |
|---|---|---|---|
| Penysarn | 18.1°C | 3.3°C | 1,066 mm |
| Amlwch 2.0 mi | 18.1°C about the same | 3.6°C about the same | 1,051 mm |
| Llanerchymedd 4.6 mi | 18.4°C about the same | 3.1°C about the same | 1,087 mm |
| Cemaes 5.8 mi | 18.2°C about the same | 3.9°C 0.6°C milder | 981 mm |
| Benllech 5.9 mi | 19.1°C 1.0°C warmer | 3.2°C about the same | 1,133 mm |
| Llangefni 9.0 mi | 19.5°C 1.4°C warmer | 3.0°C about the same | 1,148 mm |
| Bodedern 10.0 mi | 19.1°C 1.0°C warmer | 3.4°C about the same | 980 mm |
Penysarn weather by month
Average daily high and low, mean temperature and rain, 1991–2020, for the town itself (the Met Office’s HadUK-Grid).
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 7.9°C 46°F | 3.3°C 38°F | 5.6°C | 100 mm 3.9 in |
| February | 8.2°C 47°F | 3.4°C 38°F | 5.8°C | 94 mm 3.7 in |
| March | 9.6°C 49°F | 4.1°C 39°F | 6.8°C | 68 mm 2.7 in |
| April | 11.7°C 53°F | 5.6°C 42°F | 8.8°C | 60 mm 2.4 in |
| May | 14.4°C 58°F | 8.0°C 46°F | 11.2°C | 61 mm 2.4 in |
| June | 16.6°C 62°F | 10.3°C 51°F | 13.5°C | 72 mm 2.8 in |
| July | 18.1°C 65°F | 12.2°C 54°F | 15.2°C | 67 mm 2.6 in |
| August | 18.3°C 65°F | 12.5°C 55°F | 15.4°C | 83 mm 3.3 in |
| September | 16.7°C 62°F | 11.3°C 52°F | 14.0°C | 88 mm 3.5 in |
| October | 14.0°C 57°F | 9.1°C 48°F | 11.5°C | 127 mm 5.0 in |
| November | 11.1°C 52°F | 6.7°C 44°F | 8.9°C | 123 mm 4.9 in |
| December | 8.9°C 48°F | 4.5°C 40°F | 6.7°C | 122 mm 4.8 in |
| Year | 13.0°C | 7.6°C | 10.3°C | 1,066 mm |
Where Penysarn’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 Penysarn’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, 13 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 Penysarn’s climate
How warm does Penysarn get in summer?
August is the warmest month, with average highs of 18.3°C (65°F). About 1 days a year reach 25°C (77°F), fewer than 97% of UK towns.
How cold does Penysarn get in winter?
January nights average 3.3°C (38°F). The air drops below freezing on about 14 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Penysarn get?
About 1,066 mm (42 in) a year, more than 82% of UK towns. October is the wettest month (127 mm) and April the driest (60 mm).
How sunny is it?
The nearest Met Office station with a sunshine record, Valley (Anglesey) (13 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 Penysarn. 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 Penysarn →
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.