As Monday, September 21st, 2026, begins in Ireland, the day feels more like a late summer bonus than the start of autumn. If you woke up to a muggy feeling, you're not imagining it. Today is shaping up to be quite warm and humid, with a good deal of cloud cover, but there will be some bright spells, especially in the south.

We've all been there, wondering if we need a jacket or if it's a shorts kind of day. For today, it's leaning towards the latter, particularly in the east.

Today's Snapshot: Warm and Humid

Met Éireann reports some patchy drizzle and mist this morning. It's not heavy, just enough to make the air feel a bit thick. The good news is that as the day goes on, some bright or even sunny intervals are expected. The southern parts of the country will likely see the most sun.

Temperatures will range from a pleasant 17 degrees in the west to a rather warm 22 or even 23 degrees in the east. That's a significant difference, so if you're out, especially in places like Dublin or Wicklow, you might find yourself taking off a layer. Breezes will be light to moderate, generally from the southwest, contributing to the humid feel.

I often notice how the east of the country seems to get the warmest weather during these transitional seasons. It's a regular pattern, and it makes you think about how Ireland's geography influences our microclimates. So, if you're in Cork or Wexford, enjoy that extra warmth while it lasts.

What to Expect Tonight

As day turns to night, the mild and humid conditions will mostly continue. Most areas will stay dry, with some clear spells. However, watch out for patches of mist or fog, especially in lower areas. This is common on mild, still nights and can make for atmospheric, though sometimes challenging, late-night drives.

Cloud cover is expected to increase in the northwest as the night progresses. Along the northwest coast, expect some rain and drizzle to start developing overnight. Temperatures won't drop much, staying quite mild for September with lows between 12 and 15 degrees. Light southerly breezes will continue across the island.

This kind of mild night is great for stargazing, assuming the clear spells last. Just remember that mist and fog can appear quickly, so be aware of your surroundings if you're out.

Looking Ahead to Tomorrow: A Change in the Air

Tuesday, September 22nd, will bring varied weather to Ireland. Leinster and Munster are set for another mostly dry day with bright or sunny spells. There might be an isolated shower, but nothing to disrupt outdoor plans.

However, the rain and drizzle starting along the northwest coast tonight will begin to spread. It's expected to move across Ulster and Connacht through the afternoon and evening. So, if you're in Donegal or Galway, your Tuesday might start dry but likely end with wet weather.

Temperatures on Tuesday will generally be between 16 and 20 degrees for most of the country. The northwest will be a bit cooler, with highs between 14 and 16 degrees. Light southerly winds will continue.

It's a classic Irish weather scenario, isn't it? One part of the country enjoys sunshine while another gets soaked. This is why a national overview, like Met Éireann provides, is so important for understanding the bigger picture. You can always check Met Éireann directly for the most precise local information.

The National Outlook: A Cooler Turn

Beyond Tuesday, the outlook suggests a gradual shift towards cooler conditions. We're looking at a fair amount of dry weather overall, but with periods of rain or showers.

Tuesday night will see that rain in Ulster, Connacht, and west Munster slowly moving southeastwards, potentially affecting almost all areas overnight. Temperatures will be a bit cooler, ranging from 11 to 14 degrees, with light to moderate south to southwest breezes.

By Wednesday morning, the rain should gradually clear to the southeast, bringing drier, brighter weather from the west. Sunny spells will develop, and it will feel noticeably cooler. Highs on Wednesday will be between 14 and 17 degrees, with light to moderate northwesterly winds. Wednesday night looks dry with clear spells, though cloud will increase in the west. Lowest temperatures will drop to between 6 and 9 degrees.

Thursday starts dry, with bright or sunny spells in the east. The west will be cloudier, with rain developing in the west and northwest by early afternoon, spreading southwards through the day. Temperatures will be between 15 and 19 degrees, with fresh, gusty southerly winds. That rain will continue into Thursday night before clearing eastwards. Friday looks mainly dry with bright spells and a few showers, with temperatures around 15 to 18 degrees.

As we head into next weekend, the forecast leans towards unsettled conditions, with rain or showers at times and temperatures in the mid to high teens. So, while we're starting the week on a warm and humid note, it looks like autumn will firmly reassert itself by the weekend.

It's a good reminder to always keep an eye on the daily forecasts, especially when planning activities that rely on good weather. This time of year, things can change quickly!