Do you need to know, when is the best time to go to Ireland? Then you should take a look here, what weather you can expect there during the year.
The climate of Ireland is temperate maritime. The weather is modified by North Atlantic Current. You can expect mild winters and cool summers. The weather is almost consistently humid, it is very often overcast. The weather is also quite changeable and rains are not rare.
When speaking about the usual weather in this state, the information is relevant for example for these popular places: Abbeyleix, Achill Island, Adare, Aghaboe, Annascaul, Aran Islands, Ardee, Arranmore Island, Ashbourne, Athlone, Athy, Bagenalstown, Bailieborough, Balbriggan, Ballaghmore, Ballyconnell, Ballyliffin, Ballylinan, Ballymote, Ballyragget, Ballyshannon, Ballyvaughan, Baltimore, Banagher, Bantry, Belturbet, Birr, Blarney, Borris, Boyle, Bray, Brú Na Bóinne Archaeological Park, Buncrana, Bundoran, Bunratty, Burren, Burt, Cabinteely, Cadamstown, Caherciveen, Cahir, Callan, Carbury, Carlow, Carndonagh, Carrick on Shannon, Cashel, Castlebar, Castlecomer, Castlegregory, Castletown, Castletownberehaven, Castletownshend, Clara, Clifden, Cliffs of Moher, Cloghan, Cloghane Brandon, Clogherhead, Clonakilty, Clonaslee, Clonbullogue, Clonbur, Clonmacnoise, Cobh, Cong, Connemara, Cork, Craggaunowen, Croghan, Crosshaven, Cullohill, Dalkey, Dingle, Dingle Peninsula, Donegal Town, Doolin, Douglas, Drogheda, Dromahair, Dromineer, Dublin, Dundalk, Dunfanaghy, Dungarvan, Dungloe, Dunmore East, Dún Laoghaire, East Coast and Midlands, East Galway, Edenderry, Emo, Ennis, Enniscorthy, Enniskerry, Falcarragh, Fanad Peninsula, Ferbane, Fethard, Freshford, Galway, Geashill, Glencolmcille, Glendalough, Glengarriff, Glenties, Glenveagh National Park, Gorey, Gortahork, Graignamanagh, Gweedore, Hacketstown, Holycross, Horseleap, Howth, Inis Meáin, Inis Mór, Inis Oírr, Inishowen Peninsula, Inistioge, Kells, Kenmare, Kilcormac, Kildare Village, Kilfenora, Kilkee, Kilkenny, Killarney, Killorglin, Kilmore Quay, Kinnitty, Kinsale, Knock, Lahinch, Leenane, Leighlinbridge, Letterfrack, Letterkenny, Lifford, Limerick, Liscannor, Lisdoonvarna, Lismore, Longford, Lough Key, Macroom, Malahide, Mallow, Manorhamilton, Maynooth, Miltown Malbay, Moneygall, Mooncoin, Mountbolus, Mountcharles, Mountmellick, Mountrath, Mullingar, Multyfarnham, Naas, Nenagh, Northwest Ireland and Lakelands, Oldcastle, Omey Island, Oughterard, Port Laoise, Portarlington, Portmagee, Portmarnock, Querrin, Rathvilly, Roscommon, Rosscarbery, Rosses Point, Rosslare, Roundwood, Rush, Schull, Shannon, Shannon Harbour, Shannon Region, Shannonbridge, Sherkin Island, Skellig Michael, Skerries, Skibbereen, Slane, Slieve Bloom Mountains, Sligo, Southeast Ireland, Southwest Ireland, Spiddal, Stradbally, Strandhill, Swords, The Rosses, Thomastown, Thurles, Timahoe, Tipperary, Tory Island, Tralee, Trim, Tuam, Tullamore, Tullow, University College Dublin, Ventry, Waterford, West Ireland, Westport, Wexford, Youghal.
Let's look now what weather you can expect in the area around the capital and in many other cities. The warmest month here is July, the average maximum temperature is 20.2 ℃ (68.36 ℉). The average minimum temperature in this month is 11.9 ℃ (53.42 ℉). The coldest month here is January, the average maximum temperature is 8.3 ℃ (46.94 ℉). The average minimum temperature in this month is 2.6 ℃ (36.68 ℉). The most rainy month here is January, the average number of rainy days is 12.9. The least rainy month here is September, the average number of rainy days is 10. 
When travelling to some places in Ireland, always consider the altitude of the the place as well. The highest point here is Carrauntoohil (1041 m) and the lowest point is Atlantic Ocean (0 m). So the differences in altitudes in this country are not negligible and you should expect the weather to be different in places in different altitudes. Keep in mind, that the temperature usually decreases by 1.2 - 1.9 ℃ (2.2 - 3.5 ℉) per 200 m (656 ft), depending on the other conditions. (And we should add, that in the very special condition named thermal inversion even the temperature may be higher in higher altitudes.)
Typical (usual) weather in Ireland in January is this: The average highest temperature in Ireland in January is 8.3 ℃ (46.94 ℉). The average lowest temperature is 2.6 ℃ (36.68 ℉). At the beginning of January you can expect higher temperatures, the average highest temperature is around 8.45 ℃ (47.21 ℉). At the end of January you can expect higher temperatures, the average highest temperature is around 8.4 ℃ (47.12 ℉). The average number of rainy days in January is 12.9. The average rainfall is 61.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 7:34 (hours and minutes), in the middle of the month 8:03 and at the end of the month 8:50.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in February is this: The average highest temperature in Ireland in February is 8.5 ℃ (47.3 ℉). The average lowest temperature is 2.5 ℃ (36.5 ℉). At the beginning of February you can expect lower temperatures, the average highest temperature is around 8.4 ℃ (47.12 ℉). At the end of February you can expect higher temperatures, the average highest temperature is around 10.5 ℃ (50.9 ℉). The average number of rainy days in February is 10.1. The average rainfall is 48.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 8:50 (hours and minutes), in the middle of the month 9:47 and at the end of the month 10:49.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in March is this: The average highest temperature in Ireland in March is 12.5 ℃ (54.5 ℉). The average lowest temperature is 3.5 ℃ (38.3 ℉). At the beginning of March you can expect lower temperatures, the average highest temperature is around 10.5 ℃ (50.9 ℉). At the end of March you can expect lower temperatures, the average highest temperature is around 12.35 ℃ (54.23 ℉). The average number of rainy days in March is 11.4. The average rainfall is 53.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 10:49 (hours and minutes), in the middle of the month 11:53 and at the end of the month 12:56.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in April is this: The average highest temperature in Ireland in April is 12.2 ℃ (53.96 ℉). The average lowest temperature is 4.8 ℃ (40.64 ℉). At the beginning of April you can expect higher temperatures, the average highest temperature is around 12.35 ℃ (54.23 ℉). At the end of April you can expect higher temperatures, the average highest temperature is around 13.55 ℃ (56.39 ℉). The average number of rainy days in April is 11. The average rainfall is 53.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:56 (hours and minutes), in the middle of the month 13:59 and at the end of the month 14:59.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.
Typical (usual) weather in Ireland in May is this: The average highest temperature in Ireland in May is 14.9 ℃ (58.82 ℉). The average lowest temperature is 7.2 ℃ (44.96 ℉). At the beginning of May you can expect lower temperatures, the average highest temperature is around 13.55 ℃ (56.39 ℉). At the end of May you can expect higher temperatures, the average highest temperature is around 16.4 ℃ (61.52 ℉). The average number of rainy days in May is 10.8. The average rainfall is 59.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 14:59 (hours and minutes), in the middle of the month 15:53 and at the end of the month 16:34.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in June is this: The average highest temperature in Ireland in June is 17.9 ℃ (64.22 ℉). The average lowest temperature is 10 ℃ (50 ℉). At the beginning of June you can expect lower temperatures, the average highest temperature is around 16.4 ℃ (61.52 ℉). At the end of June you can expect higher temperatures, the average highest temperature is around 19.05 ℃ (66.29 ℉). The average number of rainy days in June is 10.6. The average rainfall is 66.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 16:34 (hours and minutes), in the middle of the month 16:58 and at the end of the month 16:57.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in July is this: The average highest temperature in Ireland in July is 20.2 ℃ (68.36 ℉). The average lowest temperature is 11.9 ℃ (53.42 ℉). At the beginning of July you can expect lower temperatures, the average highest temperature is around 19.05 ℃ (66.29 ℉). At the end of July you can expect lower temperatures, the average highest temperature is around 19.65 ℃ (67.37 ℉). The average number of rainy days in July is 10.8. The average rainfall is 55.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 16:57 (hours and minutes), in the middle of the month 16:32 and at the end of the month 15:50.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in August is this: The average highest temperature in Ireland in August is 19.1 ℃ (66.38 ℉). The average lowest temperature is 11.6 ℃ (52.88 ℉). At the beginning of August you can expect higher temperatures, the average highest temperature is around 19.65 ℃ (67.37 ℉). At the end of August you can expect lower temperatures, the average highest temperature is around 18.35 ℃ (65.03 ℉). The average number of rainy days in August is 11.4. The average rainfall is 73.6 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 15:50 (hours and minutes), in the middle of the month 14:56 and at the end of the month 13:57.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in September is this: The average highest temperature in Ireland in September is 17.6 ℃ (63.68 ℉). The average lowest temperature is 10.2 ℃ (50.36 ℉). At the beginning of September you can expect higher temperatures, the average highest temperature is around 18.35 ℃ (65.03 ℉). At the end of September you can expect lower temperatures, the average highest temperature is around 15.75 ℃ (60.35 ℉). The average number of rainy days in September is 10. The average rainfall is 59.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 13:57 (hours and minutes), in the middle of the month 12:55 and at the end of the month 11:52.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in October is this: The average highest temperature in Ireland in October is 13.9 ℃ (57.02 ℉). The average lowest temperature is 7.4 ℃ (45.32 ℉). At the beginning of October you can expect higher temperatures, the average highest temperature is around 15.75 ℃ (60.35 ℉). At the end of October you can expect lower temperatures, the average highest temperature is around 12.1 ℃ (53.78 ℉). The average number of rainy days in October is 12.1. The average rainfall is 80.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:52 (hours and minutes), in the middle of the month 10:50 and at the end of the month 9:49.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in November is this: The average highest temperature in Ireland in November is 10.3 ℃ (50.54 ℉). The average lowest temperature is 4.6 ℃ (40.28 ℉). At the beginning of November you can expect higher temperatures, the average highest temperature is around 12.1 ℃ (53.78 ℉). At the end of November you can expect lower temperatures, the average highest temperature is around 9.45 ℃ (49.01 ℉). The average number of rainy days in November is 11.6. The average rainfall is 74.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 9:49 (hours and minutes), in the middle of the month 8:52 and at the end of the month 8:05.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Ireland in December is this: The average highest temperature in Ireland in December is 8.6 ℃ (47.48 ℉). The average lowest temperature is 2.9 ℃ (37.22 ℉). At the beginning of December you can expect higher temperatures, the average highest temperature is around 9.45 ℃ (49.01 ℉). At the end of December you can expect lower temperatures, the average highest temperature is around 8.45 ℃ (47.21 ℉). The average number of rainy days in December is 12.3. The average rainfall is 74.3 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 8:05 (hours and minutes), in the middle of the month 7:35 and at the end of the month 7:30.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes.| Dublin | temperature: - | highest temperature: 8.6 ℃ (47.48 ℉) | lowest temperature: 2.9 ℃ (37.22 ℉) | rainfall: 74.3mm | rainy days: 12.3 |
| Cork | temperature: - | highest temperature: 8.7 ℃ (47.66 ℉) | lowest temperature: 3.9 ℃ (39.02 ℉) | rainfall: 134.1mm | rainy days: 20 |
| Shannon Airport | temperature: - | highest temperature: 9.2 ℃ (48.56 ℉) | lowest temperature: 3.8 ℃ (38.84 ℉) | rainfall: 103.3mm | rainy days: 15.2 |
| Belmullet | temperature: - | highest temperature: 9.3 ℃ (48.74 ℉) | lowest temperature: 4.5 ℃ (40.1 ℉) | rainfall: 138.6mm | rainy days: 22.8 |
| Malin Head | temperature: - | highest temperature: 8.6 ℃ (47.48 ℉) | lowest temperature: 4.4 ℃ (39.92 ℉) | rainfall: 116.3mm | rainy days: 17.4 |
| Kilkenny | temperature: - | highest temperature: 8.7 ℃ (47.66 ℉) | lowest temperature: 2.3 ℃ (36.14 ℉) | rainfall: 82.2mm | rainy days: 12.8 |
| Galway | temperature: - | highest temperature: 9.2 ℃ (48.56 ℉) | lowest temperature: 3.5 ℃ (38.3 ℉) | rainfall: 133.9mm | rainy days: 17.2 |
| Donegal | temperature: - | highest temperature: 8.5 ℃ (47.3 ℉) | lowest temperature: 3.1 ℃ (37.58 ℉) | rainfall: 132.1mm | rainy days: 0 |
| Kerry | temperature: - | highest temperature: 10.4 ℃ (50.72 ℉) | lowest temperature: 5.4 ℃ (41.72 ℉) | rainfall: 162.4mm | rainy days: 18.1 |
| Mayo | temperature: - | highest temperature: 7.9 ℃ (46.22 ℉) | lowest temperature: 2.3 ℃ (36.14 ℉) | rainfall: 124mm | rainy days: 21.6 |
| Offaly | temperature: - | highest temperature: 8.3 ℃ (46.94 ℉) | lowest temperature: 2.6 ℃ (36.68 ℉) | rainfall: 78.6mm | rainy days: 19 |
| Wexford | temperature: - | highest temperature: 9.2 ℃ (48.56 ℉) | lowest temperature: 4.1 ℃ (39.38 ℉) | rainfall: 109mm | rainy days: 19 |