Weather and seasons
May and June, then the second half of September. May and June give 14.5 to 15 hours of daylight, afternoons in the low to mid twenties, the lowest rainfall of the spring and a fully trading network, all before the August holiday squeeze. Mid-September onward gives nearly the same weather with the resort towns emptying and rates falling, at the cost of walking among the heaviest pilgrim traffic of the year.
This route is walkable in any month and so is most of its infrastructure, which sets it apart from the mountain trails in this set: it threads a near-continuous string of towns from Porto to Valenca, so food and water are rarely far apart at any time of year. What the season changes is rain, light, beds and support: October to January is the wet half at 130 to 215 mm a month and up to 15 wet days, against 17 to 40 mm in July and August, and daylight runs from 9.2 hours in December to 15.2 in June. Three seasonal services matter more here than the weather does. The lifeguards and beach bars on the Senda Litoral variant work to the northern bathing season, which opens about the middle of June; the timber boardwalks around Apulia, Ofir and Esposende take winter storm and spring-tide damage, with the municipality rebuilding them in time for that opening, so a walker between January and May may meet broken or detoured sections; and bag transfer is a summer-half service, one operator holding a standard price from mid-February to mid-November and the other running 1 April to 31 October with a winter Portuguese service that starts at Tui and never touches this trail, so November to February is a carry-everything walk.
Mild enough to walk in a shirt on a good afternoon, 13 to 15 C, but this is the second darkest month of the year and among the wettest, with 12 or 13 wet days. Fine for a walker who wants the route to themselves and does not mind arriving wet.
13-15°C high · 5-6°C low · 9.6Watch for: Atlantic fronts arriving in sequence. With 9.6 hours between sunrise and sunset, a 30 km stage means walking in the dark at one end.The winter month that works. Rainfall drops to roughly two thirds of the January figure, the light is back over ten and a half hours, and off-season room rates still apply in towns that charge holiday prices in August.
15°C high · 5-7°C low · 10.7Watch for: The boardwalk sections around Apulia, Ofir, Restinga and Belinho are the ones that take winter storms and spring tides, and Esposende typically has them repaired only in time for the June bathing season. Expect a stretch on the road or the beach instead.The driest month of the first half of the year and twelve hours of daylight, which is enough for the 25 to 30 km days this route is usually walked in. Before the Easter surge and before summer rates.
17-18°C high · 7-9°C low · 12.0Long light and warm afternoons, and a month people plan around on the assumption that it is drier than March. It is not: all three IPMA stations on this route record more rain and more wet days in April than in March.
18-19°C high · 8-10°C low · 13.4Watch for: Thunderstorms are more frequent here in April and May than in midsummer, which is the opposite of what most walkers expect.Fourteen and a half hours of light, afternoons in the low twenties, and the whole network trading before summer rates arrive. The best month here for walking long days without heat.
20-22°C high · 11-12°C low · 14.6Watch for: The nortada, the north to northwest coastal wind, starts to show in late May afternoons. Walking northbound out of Porto you have it in your face.The longest days of the year at 15 hours, rainfall down to a third of the spring figure, and the coast not under holiday pressure until the last week of the month.
23-26°C high · 14°C low · 15.2Watch for: Heat building on the last two days inland. Moncao, in the Minho valley near Valenca, averages seven days above 30 C in June against two or three on the coast at Porto.The driest month, three or four wet days, and the coast held at 24 to 26 C by the sea breeze. The turn inland up the Minho for the last 30 km is a different climate, and that is where a July day gets hard.
24-29°C high · 15°C low · 14.9Watch for: Water and shade on the Minho stretch. Moncao averages 13 days above 30 C in July and four above 35 C, against three or four above 30 C at Porto. Cafes are frequent the whole way here, which makes the heat manageable if you plan around them.The walking is much like July. What makes August awkward is everything else: it is the Portuguese holiday month on a coast of real resort towns, and Viana do Castelo is given over to the Romaria d'Agonia through the middle weeks.
25-30°C high · 15-16°C low · 13.9Watch for: Morning sea fog on the coastal sections. The Porto record averages seven fog days a month from August through October, roughly twice the July figure. Inland, four days above 35 C at Moncao.Warm, mostly dry, and the busiest single month for pilgrims on the Portuguese routes. After the middle of the month the resort towns empty and rates drop while the weather holds, which is the best fortnight of the autumn.
23-27°C high · 14-15°C low · 12.5Watch for: Rain returning. September carries twice August's rainfall and the pattern steepens sharply into October.Still 20 to 21 C and quieter every week, but the rain arrives properly: October is about twice as wet as September and one of the three wettest months of the year here. The first half is normally the better half.
20-21°C high · 11-13°C low · 11.2Watch for: The foggiest month on this coast in the Porto record, and the first of the autumn Atlantic fronts.The wettest run of the year starts and the light drops under ten hours in the same fortnight. Nothing prevents you walking, but 12 or 13 wet days and a 9.9 hour window turn a 30 km pilgrim stage into a grind.
16-17°C high · 8-10°C low · 9.9Watch for: Spring tides washing over the lower boardwalk sections, which is how the Esposende coast picks up most of its winter damage.The wettest month and the shortest days: 9.2 hours of light, about 112 hours of sunshine in the whole month at Porto, and six days on which the sun does not appear at all. Mild at 14 to 15 C, and still dark and wet.
14-15°C high · 6-8°C low · 9.2Watch for: Short days above all. Nine hours between sunrise and sunset caps a comfortable day at 20 to 25 km, so a seven-day plan needs rethinking as eight or nine.