Bethesda is among the wettest of UK towns: 2,116 mm (83 in) of rain a year
On a normal January night the air cools to about 2.6°C (37°F). Of all months, December brings the most rain and May the least. Of the 13 Gwynedd towns, it has the coolest July afternoons. For walks and days out, July and August bring highs of 17°C.
Met Office 1991–2020 averages for the town itself.
A year in Bethesda at a glance
Each month’s typical high and low, in °C.
What a year in Bethesda feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 2,116 mm of rain a year
December is the wettest month and May the driest. About 65 days a year bring 10 mm (0.4 in) or more. 2nd wettest of 13 Gwynedd towns of 2,500+.
Rain by month
Millimetres
Sunshine by month
Hours of bright sunshine at Valley (Anglesey)
25 air frosts and 3 days of 25°C a year
On about 25 nights a year the air drops below freezing, and on about under 1 days it stays below freezing all day. About 3 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 20 miles west of Bethesda, 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 Bethesda 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 |
|---|---|---|---|
| Bethesda | 17.5°C | 2.6°C | 2,116 mm |
| Tregarth 1.5 mi | 18.5°C 1.1°C warmer | 3.0°C about the same | 1,629 mm |
| Clwt-y-bont 3.8 mi | 18.9°C 1.5°C warmer | 2.7°C about the same | 2,028 mm |
| Bangor 4.4 mi | 20.0°C 2.5°C warmer | 3.4°C 0.8°C milder | 1,099 mm |
| Llanberis 5.1 mi | 17.6°C about the same | 2.6°C about the same | 2,530 mm |
| Menai Bridge 5.7 mi | 19.8°C 2.3°C warmer | 3.5°C 1.0°C milder | 1,067 mm |
| Llanrug 5.9 mi | 19.3°C 1.8°C warmer | 3.1°C 0.6°C milder | 1,597 mm |
Bethesda 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 | 7.5°C 46°F | 2.6°C 37°F | 5.1°C | 194 mm 7.6 in |
| February | 6.7°C 44°F | 1.4°C 34°F | 4.0°C | 175 mm 6.9 in |
| March | 8.2°C 47°F | 2.1°C 36°F | 5.2°C | 148 mm 5.8 in |
| April | 10.4°C 51°F | 3.7°C 39°F | 7.1°C | 131 mm 5.1 in |
| May | 13.8°C 57°F | 6.5°C 44°F | 10.1°C | 113 mm 4.4 in |
| June | 15.9°C 61°F | 8.9°C 48°F | 12.4°C | 126 mm 4.9 in |
| July | 17.5°C 63°F | 10.6°C 51°F | 13.9°C | 150 mm 5.9 in |
| August | 17.2°C 63°F | 10.8°C 52°F | 14.1°C | 168 mm 6.6 in |
| September | 15.5°C 60°F | 9.2°C 48°F | 12.3°C | 162 mm 6.4 in |
| October | 12.3°C 54°F | 6.7°C 44°F | 9.5°C | 234 mm 9.2 in |
| November | 9.3°C 49°F | 4.4°C 40°F | 6.8°C | 255 mm 10.1 in |
| December | 7.1°C 45°F | 2.2°C 36°F | 4.8°C | 261 mm 10.3 in |
| Year | 11.8°C | 5.8°C | 8.8°C | 2,116 mm |
Where Bethesda’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 Bethesda’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, 20 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 Bethesda’s climate
How warm does Bethesda get in summer?
July is the warmest month, with average highs of 17.5°C (63°F). About 3 days a year reach 25°C (77°F), fewer than 84% of UK towns.
How cold does Bethesda get in winter?
February nights average 1.4°C (34°F). The air drops below freezing on about 25 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Bethesda get?
About 2,116 mm (83 in) a year, more than almost every UK town. December is the wettest month (261 mm) and May the driest (113 mm).
How sunny is it?
The nearest Met Office station with a sunshine record, Valley (Anglesey) (20 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 Bethesda. 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 Bethesda →
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.