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Caernarfon weather

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Caernarfon weather warnings

Met Office yellow, amber and red warnings for Wales

Checking the Met Office for warnings in force for Wales…

Caernarfon weather in numbers

measured normals and 10 years of recorded weather

Caernarfon swings 15°C across the year, from 18°C highs in June to 3°C lows in January, and October is usually the wettest month in a year that brings about 1505 mm of precipitation. Over 10 years of recorded weather it averages 5 days a year at 25°C or above, 11 frost nights, and rain on 212 days.

Warmest month
June
18°C average high
Coldest month
January
3°C average low
Wettest month
October
1505 mm a year
Comfortable
4 months
June, July, August and September
Residents
9,730
share this forecast
Most accurate here
European
91/100 CheckWeather Score
Warm days
5 days
a year at 25°C or above
Frost nights
11 nights
a year below 0°C
Rain days
212 days
a year with 1 mm or more

Day counts are from the ERA5 reanalysis for Caernarfon’s grid square, 2016 to 2025, counted the same way for every city so the numbers compare. A reanalysis square is an area, not a weather station, so it is good for counting days and not for a single day’s record.

The weather map: all three models at once

Met Office, European, American side by side around Caernarfon and nearby towns.Live rain radar →
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Caernarfon hourly forecast: next 14 hours

consensus of the three models

Rain in the next 24 hours, model by model

each model's own hourly precipitation, side by side

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Caernarfon 10-day forecast, out to 14 days

where the models agree, and where they split

Caernarfon, Wales is at its warmest in Jun (average highs near 18°C) and coldest in Jan (lows around 3°C), with roughly 1505 mm of precipitation across the year. Below, compare what Met Office, European, American forecast for Caernarfon right now, and see exactly where they disagree.

We grade every model against the weather that actually happened, so you can see which forecast model is most accurate in United Kingdom before you trust any single number.

Caernarfon climate by month

average daytime high and overnight low across a typical year (1991-2020)
Jan
7°
3°
Feb
7°
3°
Mar
9°
4°
Apr
11°
5°
May
14°
8°
Jun
18°
11°
Jul
18°
13°
Aug
18°
13°
Sep
17°
11°
Oct
13°
9°
Nov
11°
6°
Dec
9°
5°

Source: 1991-2020 averages, ERA5 for this place adjusted with NASA POWER.

How the weather around Caernarfon has changed since 1995

Caernarfon sits in the same roughly 50 km square of NASA's reanalysis as Bangor. That square ran 0.5°C warmer in 2015-2024 than in 1995-2004. See the full 30-year picture on the Bangor page.

Which forecast is most accurate in Caernarfon?

CheckWeather Score, graded against the weather that actually happened
ProviderCheckWeather-scoreTempWindRainRun by
European logo
European ★ Best
91
/100rank #1
95±0.3°C97±0.8 mph8290% hitECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom
American logo
American
89
/100rank #2
93±0.4°C92±2.5 mph8290% hitNOAA / NCEP (United States)College Park, Maryland, USA
Met Office logo
Met Office
84
/100rank #3
91±0.5°C90±3.2 mph7184% hitMet Office (United Kingdom)Exeter, United Kingdom

The CheckWeather Score blends temperature, wind and rain accuracy, each measured against ERA5 (the recorded weather) over the last 30 days across 1950 cities. Lower error means a higher score. See which forecast model is most accurate in United Kingdom, how we measure forecast accuracy, or which model each weather app uses.

What do you think of the forecasts?

your vote counts

The accuracy above is the measured record. This is your opinion: which forecast service do you trust most in United Kingdom? Give each 1 to 5 stars.

Met OfficeUKMO model
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EuropeanECMWF
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AmericanNOAA GFS
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One vote per service. Anonymous: we store no personal data, only a one-way hash of your connection for a day to stop double votes.

Common questions

What's the weather in Caernarfon today?
On this page we show what Met Office, European, American each forecast for Caernarfon today, side by side and updated live. When all three agree the forecast is reliable; when they split, we flag it so you know the day is genuinely less certain.
Will it rain in Caernarfon today or tomorrow?
Check the hourly strip and 7-day forecast above. We compare rain from Met Office, European, American for Caernarfon and flag the days where the models disagree on whether showers actually arrive, which is exactly when a single app can catch you out.
Which forecast is most accurate for Caernarfon?
Over the last 30 days, the European model has been the most accurate for Caernarfon (CheckWeather Score 91/100), ahead of the American at 89. We grade every model against the recorded weather. See the UK accuracy scoreboard for the full method.
What is the warmest month in Caernarfon?
June is typically the warmest month in Caernarfon, with average highs around 18°C.
How cold does Caernarfon get?
The coldest month in Caernarfon is January, when overnight lows average about 3°C.
How much rain does Caernarfon get?
Caernarfon sees roughly 1505 mm of precipitation a year, with October usually the wettest month.

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