3-Day Weather Forecast Widget
A compact three-day outlook for a specific location - a beach, a farm shop, a festival field - with each day's high and low, the rain or snow total and the conditions expected at midday, worked out for that location's calendar days rather than UTC ones.
Live preview
Under the widget on your page: Powered by A2Z Tools
Embed code
<iframe src="https://a2z.tools/embed/w/weather-forecast-3day" title="3-Day Weather Forecast by A2Z Tools" width="100%" height="440" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="weather-forecast-3day" data-height="440"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
Daily figures are built in the browser from MET Norway's hourly rows, grouped by the local calendar day of the zone you set. A day runs from local midnight to the next local midnight, so on 25 October 2026 in London it lasts 25 hours (summer time ends at 02:00) and on 29 March 2026 only 23. The high and low are the extremes of the instantaneous temperatures that fall inside the day. Rain or snow is the sum of each row's amount weighted by the share of its period inside the day: a 6-hour step from 00:00 to 06:00 UTC seen from New York in October puts four sixths in the evening before and two sixths after midnight, and India's half-hour offset splits an hourly row in two. The icon is the conditions forecast for 12:00 local time; for the rest of today once midday has passed it shows the most severe conditions still to come (thunder over heavy rain over showers over cloud). Why only three days: the proxy keeps 72 rows, hourly for about 2.5 days then 6-hour steps, so a later day would rest on four samples.
Method
- Local day = [00:00, next 00:00) in the IANA zone, found with Intl offsets (23, 24 or 25 hours)
- High = max(temperature of rows starting in the day); Low = min(same rows)
- Rain/snow = sum over rows of amount x overlap(row period, day) / row period, rounded to 0.1 mm
- Icon = symbol of the row whose period contains 12:00 local; else the highest-severity symbol among the day's rows
- Severity order: thunder > heavy > normal > light precipitation (snow > sleet > rain) > fog > cloudy > partly cloudy > fair > clear
- Flags: 'From 19:00' when today started before the first row; 'Partly 6-hour steps' when a 6-hour row contributes
Worked examples
The day the clocks go back
Inputs: London (Europe/London), now Sat 24 Oct 2026 12:00 UTC, hourly rows of 0.1 mm
Result: Sun 25 Oct: 25-hour day, 2.5 mm; Mon 26 Oct: 2.4 mm
Local 25 Oct runs from 24 Oct 23:00 UTC to 26 Oct 00:00 UTC because BST ends at 01:00 UTC; grouping by UTC day would give 2.4 mm.
A 6-hour amount across local midnight
Inputs: New York (EDT, UTC-4), 6 mm forecast for 00:00-06:00 UTC on 6 Oct
Result: 5 Oct: 4.0 mm; 6 Oct: 2.0 mm
00:00-06:00 UTC is 20:00-02:00 EDT: four of the six hours fall on 5 October local time.
Half-hour time zone
Inputs: Kolkata (UTC+5:30), 1 mm in the 18:00 UTC hourly row
Result: 1 Oct: 0.5 mm; 2 Oct: 0.5 mm
18:00-19:00 UTC is 23:30-00:30 IST, so half the amount belongs to each local day.
Limitations
- Three days at most; the third may rest partly on 6-hour steps (flagged), where the high and low come from fewer samples.
- Totals assume rain falls evenly within a 6-hour step when that step straddles local midnight.
- Model forecasts for a grid cell of 2.5-9 km; mountains and coasts can see very different local weather.
- No warnings, wind or UV columns - add the Weather Card for current wind and link your national weather service for warnings.
Where publishers use it
- An outdoor activity centre listing the next three days beside its booking calendar
- A farm shop or pick-your-own farm telling families whether Saturday looks dry enough for the fields
- A wedding or festival venue page in the run-up to an event weekend
- A surf school or sailing club page next to its tide table
- A garden centre blog post on planting out, reminding readers of tonight's low
Questions
Why three days and not seven?
A2Z's proxy keeps the first 72 rows of MET Norway's forecast: hourly for about 60 hours and then 6-hourly. Beyond the third day a high and low would come from just four snapshots (00, 06, 12 and 18 UTC), which can miss the real afternoon maximum by several degrees, so the widget stops at three. A seven-day version needs the server to keep MET's 6-hour minimum and maximum temperatures as well.
How is the day's icon chosen?
It is the symbol for the period that contains 12:00 local time, which represents the bulk of the daylight hours better than a 24-hour worst case. Later today, after midday, it switches to the most severe symbol still ahead, so an evening thunderstorm is not hidden behind a sunny noon that has already passed. The rule is printed under the list.
Which midnight does a day start at?
The place's local midnight, using the zone you set (for example Europe/Madrid), not UTC. On a clock-change day the day really is 23 or 25 hours long and every hour is counted once. Leave the zone empty and each visitor's own zone is used and labelled, which suits only places in that zone.
Why does today say From 19:00?
The forecast starts at the current hour, so today's high, low and total cover only what is left of the day. The flag shows when that partial day begins so a reader does not compare it with a full day. A third day may also say Partly 6-hour steps when the hourly data ran out during it.
What do the rain or snow figures mean?
Liquid-equivalent precipitation in millimetres (or inches with US units) expected over that local day, summed from MET's 1-hour or 6-hour amounts. 0.0 mm means none forecast; snow is reported as melted water, so 10 mm of snow water is very roughly 10 cm of fresh snow.
Sources
- Locationforecast data model - MET Norway (Norwegian Meteorological Institute) . Short range in 1-hour steps, medium range in 6-hour steps; next_1_hours only in the short range; precipitation_amount in mm for the period; ECMWF 0-10 days outside the Nordic area. Checked 2026-10-01.
- Terms of Service - MET Norway . Attribution under CC BY 4.0 with a licence link and an indication of changes; caching rules followed by A2Z's proxy. Checked 2026-10-01.
- Time Zone Database - IANA . Daylight-saving rules used by the browser to place local midnights; UK summer time 2026 ends 25 October 01:00 UTC. Checked 2026-10-01.
Cite or recommend this tool
If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.
A2Z Tools 3-Day Weather Forecast https://a2z.tools/embed/weather-forecast-3day
<a href="https://a2z.tools/embed/weather-forecast-3day">A2Z Tools 3-Day Weather Forecast</a>
[A2Z Tools 3-Day Weather Forecast](https://a2z.tools/embed/weather-forecast-3day)
3-Day Weather Forecast by A2Z Tools - https://a2z.tools/embed/weather-forecast-3day
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