Is it raining now in Bon-y-maen?
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Last update: 21:00, 5 Oct 2026
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Rain in Bon-y-maen: What You Need to Know
Bon-y-maen sits on the eastern side of the River Tawe above Swansea, with Kilvey Hill rising directly behind the village and the built-up streets of Swansea and Llansamlet spreading along the valley floor below. Checking a Bon-y-maen rain radar takes seconds, and hyperlocal radar shows which part of town the rain is actually crossing.
Fronts cross the Irish Sea and the Bristol Channel and meet ridge after ridge of high ground. Orographic lift produces heavy rain over the valley heads, and the steep, narrow valleys send that runoff to the river towns within hours. Rain reaching Bon-y-maen off Swansea Bay has to climb Kilvey Hill almost as soon as it crosses the coast, so the hill behind the village often takes a heavier band than the flat ground down by the Tawe. Wind funnelling up the Tawe valley can also push showers further inland than a forecast for the wider Swansea area suggests.
RainViewer draws the live rain radar for Bon-y-maen, Wales, from Met Office data, with real-time rain refreshed on every 5-minute radar update. The live map shows whether a shower is still crossing Swansea Bay or already lifting over Kilvey Hill, which a forecast for Bon-y-maen cannot tell you.
Rain by Season in Bon-y-maen
Autumn and winter frontal season (September to January)
From September to January, Atlantic depressions and named storms keep persistent rain falling over the hills, and once the ground is saturated the valley rivers rise quickly. The first places to feel it are valley roads, mountain passes and streets that lie low. Atlantic fronts and named storms bring heavy rain off the bay, and the hillside streets of Bon-y-maen and the low ground by the Tawe both feel it.
Transition months (February to April)
Showers and hail alternate on Kilvey Hill in spring, and walks up onto the hill are the plans most often cut short. Between February and April, fronts alternate with hail, sleet and wet snow settling on the tops. The showers involved are narrow enough to defeat most forecasts, so hill walks and weekend rugby fixtures carry the greatest exposure to a sudden change underfoot.
Summer season (May to August)
Summer showers off Swansea Bay are short, and views from Kilvey Hill and time in the village depend on gaps between them. Rain is less frequent, but heavy showers and thunderstorms can form over the hills on warm afternoons. Festivals, coastal trips and mountain walks depend on short dry windows.
Why You Need a Rain Radar in Bon-y-maen
Walkers on Kilvey Hill
Kilvey Hill rises steeply right behind the village and catches showers before the lower streets do. Watch the cell approach on the map and decide whether to start the climb or wait.
Commuters into Swansea city centre
The road and footpaths down into Swansea from Bon-y-maen drop steeply and carry heavy rain fast. Check the radar and decide whether to leave now or wait.
River Tawe path users
The path along the River Tawe below the village can flood after heavy rain higher up the valley. Check the radar for rain over the hills before walking the riverside.
Village shop and community visitors
Residents heading to the local shops and community hall in Bon-y-maen can see whether a shower is still crossing the bay or already over the village before stepping out.
RainViewer Radar Coverage in Bon-y-maen
RainViewer shows UK precipitation using data from the Met Office, the national weather service, which runs a network of C-band dual-polarization weather radars. The Met Office network also feeds the European OPERA composite, and the RainViewer map refreshes with each new scan, about every 5 minutes. From Bon-y-maen the map also covers Swansea, Llansamlet and Morriston.
Bon-y-maen Rain Radar: Frequently Asked Questions
- How does rain affect a walk up Kilvey Hill?
Kilvey Hill rises directly behind Bon-y-maen and lifts showers crossing Swansea Bay almost as soon as they reach the coast, so the hill can be in cloud while the streets below stay dry. Walkers watch the radar rather than the view from their front door. RainViewer shows the shower building over the hill.
- Does rain affect the road down into Swansea from Bon-y-maen?
Yes, the steep road down from Bon-y-maen into Swansea city centre carries fast-running water in heavy rain, and spray builds where the gradient is steepest. Look at the map before setting off. RainViewer marks the cell's position, so it is clear whether it is still coming or already gone.
- Does Bon-y-maen flood when it rains?
Bon-y-maen sits on higher ground than the Tawe valley floor, so the village itself rarely floods, but the riverside path and low ground toward Llansamlet can be under water after heavy or prolonged rain. The hillside streets stay clear. The radar shows if another shower is on the way.
- When is the best time to visit Bon-y-maen to avoid rain?
May to August is the best window to visit Bon-y-maen, when Kilvey Hill and the views over Swansea Bay are at their most pleasant. Spring can still bring hail on the hill. Check the radar in the morning and plan the walk around the dry gap.
- Why can it rain on Kilvey Hill while the Tawe valley floor stays dry around Bon-y-maen?
Kilvey Hill lifts showers crossing Swansea Bay and wrings extra rain from the band as it climbs, so the hill can be wet while the Tawe valley floor below stays dry until the same band moves across. RainViewer draws each shower where it actually is, which is why a look at Kilvey Hill and the Tawe valley floor can give different answers.
- What is the advantage of a radar map over a rain forecast for Bon-y-maen?
A rain forecast for Bon-y-maen gives a single probability for a wide area, while the radar map shows the shower's real shape and position as Met Office scans arrive. Wales is covered by Met Office C-band radar, and its dual-polarization data tells rain, sleet and hail apart even up on the Brecon Beacons and the valley tops. That hyperlocal detail is what lets you judge one street rather than the whole town.
- What can I do with RainViewer in Bon-y-maen beyond checking current rain?
Set a rain alert on Kilvey Hill or the village centre and RainViewer warns you before rain arrives. That lets you time a walk or a trip into Swansea. The 2-hour forecast in 5-minute slices shows the next gap, and saved locations track Llansamlet and Morriston.
Track Rain in Bon-y-maen in Real Time
A climb up Kilvey Hill and a walk down into Swansea both depend on a dry gap, and RainViewer shows the next one.
Rain in Bon-y-maen arrives from the west in bands, and the valleys catch each one first.
Your forecast for Bon-y-maen says showers this evening. RainViewer's live hyperlocal radar shows the cell already lifting over Kilvey Hill with the village centre still dry, which decides whether the walk starts now.
Track rain in Bon-y-maen — free Upgrade to Essential for alerts, forecasts, and full radar history
2-hour forecast in 5-minute slices
Slice the next two hours into 5-minute steps and pick the gap for the walk up Kilvey Hill.
Rain alerts before arrival
An alert on the village centre arrives while the rain is still on its way, and that decides whether to head up the hill now or wait.
Direction arrows on the map
In Bon-y-maen the wet weather tends to come from the west and south-west, off the Irish Sea and the Bristol Channel, and the arrows show the track of every shower.
48 hours of radar history
Scroll back over Swansea Bay below Bon-y-maen to see what actually fell overnight.
Multiple locations
Track the village centre, Kilvey Hill and the Tawe riverside path together and compare which one is dry.
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