lnf.cymru stimulus sheet · Humanities · Year 6

Rainfall at two weather stations in Wales

Station A, Station B, the holiday website and every rainfall number on this sheet are invented for practice. The numbers follow the real pattern of rain in Wales.

1. The two weather stations

A weather station has a rain gauge. Every day, the rain that falls into it is measured in millimetres (mm). The daily amounts are added up to give a total for each month.

The numbers on this sheet are the total rain for each month of one year.

Why do mountains get more rain?

The mountains of Eryri are among the wettest places in the UK. This is why:

  1. In Wales, the wind most often blows from the south-west, across the Atlantic Ocean. The air picks up lots of water from the sea.
  2. When this wet air reaches the mountains, it has to rise up over them.
  3. Higher up, the air is colder. Cold air cannot hold as much water, so the water turns into tiny drops. The drops make clouds.
  4. The drops join together and get heavier, then fall as rain.
  5. By the time the air has crossed the mountains, it has lost a lot of its water. So places on the far side of the mountains often get less rain.

On low land by the coast, the air is not pushed up as much, so less rain falls. In the west of Wales, it is usually wetter in autumn and winter than in spring and summer.

Diagram: wet air from the Atlantic Ocean blows onto the land, rises over the mountains, cools and makes clouds and rain. Less rain falls on the far side. Atlantic Ocean Coast Mountains Far side Wet air from the sea 1. Air is pushed up 2. It cools: clouds and rain 3. Drier air comes down

2. Chart 1: Station A, a valley in Eryri (bar chart)

The numbers go up in steps of 50 mm. Each faint line is 10 mm.

Bar chart of monthly rainfall at Station A, a valley in Eryri. The axis goes from 0 to 350 mm in steps of 50 mm. 0 50 100 150 200 250 300 350 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Rainfall (mm)

3. Chart 2: Station B, a beach village on the Pembrokeshire coast (line graph)

The numbers go up in steps of 10 mm. Each faint line is 5 mm.

Line graph of monthly rainfall at Station B, a beach village on the Pembrokeshire coast. The axis goes from 0 to 120 mm in steps of 10 mm. 0 10 20 30 40 50 60 70 80 90 100 110 120 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Rainfall (mm)

4. Chart 3: Station B on a holiday website

This chart was made by an invented holiday website. It uses the same Station B numbers as Chart 2. Look very carefully at where the numbers on the side start. Each faint line is 5 mm.

“Come in May! Look how dry it is!”

Bar chart of Station B rainfall drawn by an invented website. The axis starts at 40 mm, not 0. 40 50 60 70 80 90 100 110 120 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Rainfall (mm)

5. The table: rainfall each month (mm)

Use this table to check what you read from the charts.

MonthStation A, a valley in Eryri (mm)Station B, a beach village on the Pembrokeshire coast (mm)
January340100
February26075
March25070
April16050
May14045
June13050
July15055
August18065
September22075
October300100
November320110
December310105

Seasons on this sheet: winter is December, January and February. Spring is March, April and May. Summer is June, July and August. Autumn is September, October and November.