Months of the year
The climate of Ireland is both very mild and quite changeable and unpredictable. Here is our guide to the different times of year. It is helpful to think of April 15th to October 15th as a six-month window for cycle touring. The 6 weeks before and after this can still be good for day trips. Avoid December, January and February, although there are some sunny days which are cold but can be good for short rides.
May, June, July, August, September
Long, long days with sunny spells and some showers. Good weather can often last several days. Hottest temperatures rarely go above 28C in the midlands and 25C on the coasts. Even if it does get hotter than this it will only be by a little bit. There are plenty of overcast but dry days which have comfortable temperatures and are perfect for cycling. Prolonged rain is infrequent.
Days noticeably shorten during September. June 21st has 17 hours of daylight (from around 5am to 10pm) in Dublin, with an extra 20 minutes in the north of the island. Add to that an extra hour of twilight in both the morning and evening and you only have about 5 hours of darkness.
Any good weather is a hangover from September but it quickly gets colder and wetter.
November, December, January
Only the toughest of the tough do any significant cycling. Plenty of rain and cold temperatures. Nevertheless, it rarely gets below 0C, and there are numerous crisp sunny days when a short ride is enjoyable if you wrap up warm. Put on a woolly hat on under your helmet, stick on a second pair of socks and wear a jacket. Keep an eye on the weather forecast and you might have a fine day out.
Snow in Ireland is rare. Most years it does not stay on the ground for any significant period of time outside of the mountains.
The days start to lengthen but it remains cold and often wet.
March and April
The days lengthen more and long rides become more viable for people riding for fun as opposed to needing to train. Weather is very variable and difficult to plan for.
It is helpful to think of April 15th to October 15th as a six-month window for cycle touring. The 6 weeks before and after this can still be pretty good for day trips. Avoid December, January and February, although there are some sunny days which are cold but can be good for short rides.