The 30-year period of averages currently in use by the Meteorological Office is 1981 to 2010.
All data is recorded using standard Meteorological Office equipment, thermometers that are tested and certified, rain gauges and sun recorders, set on a standard site inspected by the meteorological office. On any one day the temperature, rainfall and sunshine in different parts of the Borough can vary greatly, readings are often queried by people using untested and improperly installed equipment.
The temperatures below are the monthly averages, specific daily data can be found on the What was it like page.
The Met Office divides the year up into precise 3 monthly periods:
|January||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||75.9||67.2||8.6||4.0||Lowest sun since 2002 .The greatest rainfall was 28.1 mm on Tuesday 22nd. Eighth consecutive month that has seen more than the monthly average rainfall Rain fell on 19 days; hail fell on 28th, snow on 16th and 18th.|
|February||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||57.9||89.5||8.5||3.4||Coldest February since 2006. Ground Frost was recorded on 13 occasions; lowest reading was minus 5.0 degrees on Sunday 3rd. Hail Saturday and Sunday 23rd and 24th. Ground Frost was recorded on 13 occasions; lowest reading was minus 5.0 degrees on Sunday 3rd.|
End of winter: Rainfall 343.4mm, 154% of the 30-year average, wettest winter since 1995. Sunshine 211.0 hours, 102.0% of the 30-year average. Temperatures were very close to the seasonal average.
|March||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||61.8||128.7||10.3||4.7||Coldest March since 1880 and the wettest since 2001. Least amount of sunshine since 1984. Flakes of snow 0920 on Thursday 17th and at 0630 and 1900 on Wednesday 27th.|
|April||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||49.4||196.3||12.5||5.7||Joint second coldest April with 1978, and the lowest Maximum average since 1986 which was just 9.6oC; and the lowest minimum temperatures since 1990, Snow flakes 1620 on April 4th.|
|May||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||46.4||223.6||15.5||8.8||May turned out to be an average month, except for the persistent wind. No huge gusts, but the wind was there all the time lowering the warm feeling that the sunshine promised.|
End of Spring; Sunshine 94% and rainfall 132% of seasonal average, Temperatures: Maximum 1.7oC below and Minimum 1.5oC below seasonal average.
|June||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||45.3||225.3||18.0||11.0||Lowest June rainfall for ten years and just 20% of 2012's record rainfall|
|July||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||37.1||239.2||20.2||13.0||First 3 weeks dry, last 10 days saw a month's average rainfall. Sunshine 24% up on the average.|
|August||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||47.8||219.6||20.3||13.8||Another nice sunny month, sunniest August for 6 years. Slightly below average rainfall|
End of Summer; Sunshine 119% and Rainfall just below the seasonal average. Minimum temperature was 0.8oC and Maximum temperature 0.7oC above seasonal average. Driest and warmest summer since 2006.
|September||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||56.4||171.6||18.5||12.2||A dry month and quite warm month with a disappointing amount of sunshine.|
|October||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||85.1||123.9||15.2||9.9||Average October until the wrath of St. Jude descended gusts between 29 and 69 MPH during the last week.|
|November||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||93.1||85.8||11.9||6.8||A little on the cool side but all in all a very nice month. Air frost was recorded on Wednesday 20th and there were 9 occasions of ground frost.|
End of Autumn: Sunshine slightly above average, Rainfall slightly below the seasonal average, Minimum temperature was 0.7oC and Maximum temperature 0.8oC above seasonal average.
|December||Rainfall mm||Sunshine Hrs.||Maximum oC||Minimum oC||Notes|
|30 year average||88.6||63.6||9.1||4.3||A very wet month wettest since 1989, and as with last year one of the warmest Decembers on record, 1 air frost, but 11 ground frosts very windy, also Lightning, thunder and hail.|
The average annual sunshine is 1855 hours 18 minutes, 2013 saw an increase in sunshine in a year that was pretty bad all over the country recording 1863 hours and 12 minutes, the sunniest day was 14th June with 14 hours and 42 minutes.
The average annual rainfall in Weymouth is 744.8 millimetres, 2013 saw a 17% increase (124.4 mm) above the 30-year average, recording a total of 869.2mm. June and September were all drier than average. January, March October and December were well above their averages, making this a wet year, but falling well below the 2012 total of 1133.5mm.
The prevailing wind for Weymouth is from the southwest, 119 days the wind came from the southwest quadrant, 56 days came from the southeast quarter, 108 from the northeast direction, 71 from the northwest and 11 days were calm at the 0900 observation. Gale force winds, i.e. wind at a speed of 34 knots or more, for a period of 10 minutes, or for gust exceeding 43 knots occurred on 27 occasions, gusts occurred more frequently but not for extended periods. The highest being 69 knots on 27th October.
2013 was an average year for temperature with both the Maximum and Minimum. The warmest day was 8th July at 25.8oC.
October and December were over 2 degrees above the 30-year average, whilst March was the coldest month; the highest minimum temperature was on 22nd July at 17.5oC.
The air temperature dropped to zero or below on 18 days, most of these were in March. Lowest air temperature was -2.6oC on 12th March.
Occurred on 70 occasions throughout the year, January 16 times, February 17 times, March 14 times, and April 9 times, 9 in November, and on 5 occasions during December, the lowest ground temperature was -5.0oC on 21st January.
The sea temperature is measured in Weymouth Bay from the Pleasure Pier, (and is mainly recorded for the convenience of the bathers, whether they be local or visitors), the temperature of the water in the bay varies considerably from day to day depending on tide and wind, the rate of cooling and warming is a lot slower that of the air temperature, and in the winter is often a lot warmer than the air temperature. The temperature is measured 1 metre below the surface. The sea temperature was mainly below the 30-year average, from 4o in April to 18.5oC on 5th September.
5 occurrences of thunder were recorded, 12th January, 21st July, 7th September, 19th October and 25th December.
Hail was recorded 4 times 12th January, 16th March, 16th September, and 25th December.
Snow, a rare phenomenon in Weymouth saw light flakes on 16th and 18th January, March 10th, 11th, 26th and 27th, and April 4th.
Fog is 'wet air', not to be confused with haze, which is 'dirty but dry air'. When assessing visibility, fog reduces visibility to 1000 metres, whilst thick fog brings visibility down to 400 metres. Fog was observed on 24th and 25th April, 6th May, 20th and 26th June, 31st July, 4th , 24th and 26th September, Mist and haze was present on several occasions during the year.