UTC Offset
UTC+01:00
Carmarthen, United Kingdom Snapshot 2026
Where is Carmarthen?
Carmarthen, United Kingdom
- Continent
- Europe
- Country
- United Kingdom
- City
- Carmarthen
- Population
- 15.9K
- Coordinates
- 51.86°, -4.31°
Carmarthen is a city in United Kingdom with a population of approximately 15.9K. Average temperatures range from 3°C (38°F) in January to 20°C (67°F) in July. The best time to visit is May, June, July, August, September.
Time in Carmarthen right now
Open full time & time zone page 06:30 30
Tuesday, June 16, 2026
IANA time zone
Europe/London
Daylight saving
DST in effect
GMT / BST
Next DST change
October 25
backward -1h
Live weather in Carmarthen
Daylight in Carmarthen today
View full sunrise & sunset page Sunrise
Sunset
Day length
16h 41m
Climate normals for Carmarthen
Long-term monthly averages based on historical data.
January
Poor 
February
Poor March
Poor April
Fair May best
Good June best
Good July best
Excellent August best
Good September best
Fair October
Poor November
Poor December
Wet | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 8°C / 3°C | 4°C / -1°C | 15days (125 mm) Wet | 4h Fair | 88% Very Muggy | 1 Low | Poor | View Details |
| February | 9°C / 4°C | 4°C / -1°C | 15days (117 mm) Wet | 5.4h Fair | 85% Humid | 1.5 Low | Poor | View Details |
| March | 10°C / 4°C | 6°C / 0°C | 16days (110 mm) Wet | 7.4h Good | 83% Humid | 3.1 Moderate | Poor | View Details |
| April | 13°C / 6°C | 10°C / 2°C | 12days (71 mm) Wet | 10h Excellent | 78% Humid | 4.3 Moderate | Fair | View Details |
| May best | 16°C / 9°C | 15°C / 6°C | 12days (76 mm) Wet | 11.4h Excellent | 78% Humid | 5.5 High | Good | View Details |
| June best | 19°C / 12°C | 18°C / 10°C | 15days (87 mm) Wet | 11.5h Excellent | 80% Humid | 6.1 High | Good | View Details |
| July best | 20°C / 14°C | 19°C / 12°C | 14days (86 mm) Wet | 11.3h Excellent | 80% Humid | 5.5 High | Excellent | View Details |
| August best | 20°C / 14°C | 19°C / 12°C | 15days (108 mm) Wet | 10.4h Excellent | 82% Humid | 5.1 High | Good | View Details |
| September best | 18°C / 12°C | 16°C / 10°C | 15days (140 mm) Wet | 7.9h Good | 84% Humid | 3.5 Moderate | Fair | View Details |
| October | 14°C / 10°C | 12°C / 7°C | 17days (156 mm) Wet | 6.3h Fair | 86% Very Muggy | 2.3 Moderate | Poor | View Details |
| November | 11°C / 7°C | 7°C / 3°C | 17days (150 mm) Wet | 4.5h Fair | 87% Very Muggy | 1.2 Low | Poor | View Details |
| December | 9°C / 5°C | 5°C / 1°C | 18days (170 mm) Wet | 3.3h Poor | 89% Very Muggy | 0.8 Low | Wet | View Details |
Monthly Temperatures
HighLow
Line chart showing monthly temperatures. Jan: 8°C / 3°C . Feb: 9°C / 4°C . Mar: 10°C / 4°C . Apr: 13°C / 6°C . May: 16°C / 9°C . Jun: 19°C / 12°C . Jul: 20°C / 14°C . Aug: 20°C / 14°C . Sep: 18°C / 12°C . Oct: 14°C / 10°C . Nov: 11°C / 7°C . Dec: 9°C / 5°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 125 mm. Feb: 117 mm. Mar: 110 mm. Apr: 71 mm. May: 76 mm. Jun: 87 mm. Jul: 86 mm. Aug: 108 mm. Sep: 140 mm. Oct: 156 mm. Nov: 150 mm. Dec: 170 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 88%. Feb: 85%. Mar: 83%. Apr: 78%. May: 78%. Jun: 80%. Jul: 80%. Aug: 82%. Sep: 84%. Oct: 86%. Nov: 87%. Dec: 89%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 28 km/h . Feb: 31 km/h . Mar: 27 km/h . Apr: 23 km/h . May: 21 km/h . Jun: 22 km/h . Jul: 22 km/h . Aug: 24 km/h . Sep: 25 km/h . Oct: 27 km/h . Nov: 28 km/h . Dec: 30 km/h .
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 7°C . Feb: 7°C . Mar: 8°C . Apr: 11°C . May: 15°C . Jun: 18°C . Jul: 19°C . Aug: 19°C . Sep: 18°C . Oct: 15°C . Nov: 11°C . Dec: 8°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 1. Feb: UV 2. Mar: UV 3. Apr: UV 4. May: UV 6. Jun: UV 6. Jul: UV 6. Aug: UV 5. Sep: UV 4. Oct: UV 2. Nov: UV 1. Dec: UV 1.
Frequently Asked Questions
Carmarthen has a population of approximately 15.9K.
The best months to visit Carmarthen are May, June, July, August, September, when temperatures are pleasant and rainfall is lower.
Carmarthen receives approximately 1396mm of rainfall annually across 181 rainy days.
Carmarthen is located in United Kingdom, in the Europe region.