Efail Isaf sits near the top of UK towns for rain, with 1,599 mm (63 in) a year
Peak summer warmth arrives in July, with afternoons near 21.0°C (70°F). Temperatures cover 19°C across the year, low to high. Winters are mild: January nights here are milder than in 70% of UK towns. Windscreens need scraping on about 40 mornings a year, the nights the air drops below 0°C.
Met Office 1991–2020 averages for the town itself.
A year in Efail Isaf at a glance
Each month’s typical high and low, in °C.
What a year in Efail Isaf feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,599 mm of rain a year
December is the wettest month and May the driest. About 54 days a year bring 10 mm (0.4 in) or more.
Rain by month
Millimetres
40 air frosts and 10 days of 25°C a year
On about 40 nights a year the air drops below freezing, and on about under 1 days it stays below freezing all day. About 10 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 Cardiff Bute Park
Cardiff Bute Park is 7.1 miles south-east of Efail Isaf, 9 m (30 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 |
|---|---|---|---|---|
| January | 8.6°C | 2.5°C | 127 mm | 8.1 |
| February | 9.1°C | 2.5°C | 93 mm | 7.5 |
| March | 11.3°C | 3.9°C | 85 mm | 3.9 |
| April | 14.4°C | 5.7°C | 72 mm | 1.4 |
| May | 17.4°C | 8.5°C | 78 mm | 0.0 |
| June | 20.1°C | 11.3°C | 73 mm | 0.0 |
| July | 21.8°C | 13.1°C | 84 mm | 0.0 |
| August | 21.4°C | 12.9°C | 105 mm | 0.0 |
| September | 19.1°C | 10.7°C | 87 mm | 0.0 |
| October | 15.2°C | 8.0°C | 128 mm | 1.0 |
| November | 11.6°C | 4.9°C | 131 mm | 3.7 |
| December | 9.1°C | 2.9°C | 140 mm | 8.3 |
| Year | 14.9°C | 7.2°C | 1,201 mm | 34 |
Met Office historic station data, Cardiff Bute Park, 1991–2020 months averaged (a month needs 20 of the 30 years; estimated values counted, missing months left out). Sunshine: Campbell-Stokes recorder.
How Efail Isaf 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 Mid Glamorgan 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 |
|---|---|---|---|
| Efail Isaf | 21.0°C | 2.1°C | 1,599 mm |
| Church Village 0.7 mi | 21.0°C about the same | 2.1°C about the same | 1,599 mm |
| Taff's Well 1.9 mi | 21.3°C about the same | 1.8°C about the same | 1,462 mm |
| Beddau 1.9 mi | 21.0°C about the same | 2.0°C about the same | 1,590 mm |
| Pentyrch 2.0 mi | 21.1°C about the same | 1.7°C about the same | 1,454 mm |
| Creigiau 2.5 mi | 20.9°C about the same | 1.7°C about the same | 1,433 mm |
| Pontypridd 3.0 mi | 20.9°C about the same | 2.1°C about the same | 1,686 mm |
Efail Isaf 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 | 7.8°C 46°F | 2.1°C 36°F | 4.9°C | 168 mm 6.6 in |
| February | 8.1°C 46°F | 1.9°C 35°F | 4.9°C | 133 mm 5.2 in |
| March | 10.3°C 50°F | 3.0°C 37°F | 6.7°C | 114 mm 4.5 in |
| April | 13.4°C 56°F | 4.7°C 40°F | 9.1°C | 94 mm 3.7 in |
| May | 16.6°C 62°F | 7.4°C 45°F | 12.0°C | 93 mm 3.7 in |
| June | 19.3°C 67°F | 10.4°C 51°F | 14.8°C | 94 mm 3.7 in |
| July | 21.0°C 70°F | 12.2°C 54°F | 16.6°C | 107 mm 4.2 in |
| August | 20.5°C 69°F | 12.0°C 54°F | 16.3°C | 127 mm 5.0 in |
| September | 18.1°C 65°F | 9.9°C 50°F | 14.0°C | 121 mm 4.8 in |
| October | 14.2°C 58°F | 7.3°C 45°F | 10.8°C | 175 mm 6.9 in |
| November | 10.5°C 51°F | 4.4°C 40°F | 7.4°C | 176 mm 6.9 in |
| December | 8.1°C 47°F | 2.4°C 36°F | 5.2°C | 196 mm 7.7 in |
| Year | 14.0°C | 6.5°C | 10.2°C | 1,599 mm |
Where Efail Isaf’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 Efail Isaf’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 Cardiff Bute Park, 7.1 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 Efail Isaf’s climate
How warm does Efail Isaf get in summer?
July is the warmest month, with average highs of 21.0°C (70°F). About 10 days a year reach 25°C (77°F), fewer than 52% of UK towns.
How cold does Efail Isaf get in winter?
February nights average 1.9°C (35°F). The air drops below freezing on about 40 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Efail Isaf get?
About 1,599 mm (63 in) a year, more than 97% of UK towns. December is the wettest month (196 mm) and May the driest (93 mm).
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 Efail Isaf. 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 Efail Isaf →
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