Might your date selection depend upon the variables you wish to download?
If so, check here (note - there may be some gaps):
| Variable | From | Until
| ---- | Variable | From | Until
|
|---|
| Air pressure
|
| Station pressure as read (ins) | 19450615 | 19680930
| | | Station pressure (mb) | 19450615 | 19680930
|
| 09GMT temperature
|
| Dry bulb temp (degF) | 19450615 | 19680930
| | | Wet bulb temp (degF) | 19450615 | 19680930
|
| Dry bulb temp (degC) | 19450615 | 19680930
| | | Wet bulb temp (degC) | 19450615 | 19680930
|
| Dew point (degC) | 19450615 | 19680930
| | | Vapour pressure (mb) | 19450615 | 19680930
|
| Relative humidity (%) | 19450615 | 19680930
|
| temp. extremes
|
| Maximum temperature (degF) | 19450615 | 19680930
| | | Minimum temperature (degF) | 19450615 | 19680930
|
| Grass minimum temp (degF) | 19450615 | 19680930
| | | Maximum temperature (degC) | 19450615 | 19680930
|
| Minimum temperature (degC) | 19450615 | 19680930
| | | Grass minimum temp (degC) | 19450615 | 19680930
|
| Mean daily temp (degC) | 19450615 | 19680930
| | | Daily temp range (degC) | 19450615 | 19680930
|
| soil temperature
|
| 10cm soil temp (degF) | 19450615 | 19680930
| | | 20cm soil temp (degF) | 19450615 | 19680930
|
| 10cm soil temp (degC) | 19450615 | 19680930
| | | 20cm soil temp (degC) | 19450615 | 19680930
|
| cloud and wind
|
| Cloud cover (oktas) | 19450615 | 19680930
| | | Wind direction (point) | 19450615 | 19680930
|
| Wind direction (deg/10) | 19450615 | 19680930
| | | Wind speed (Beaufort scale) | 19450615 | 19680930
|
| Wind speed (kn) | 19450615 | 19680930
|
| weather and visibility
|
| Present weather (code) | 19450615 | 19680930
| | | Today snow(5) or sleet(1) | 19450615 | 19680930
|
| 50% snow cover at 09GMT(1) | 19450615 | 19680930
| | | Today thunder heard(1) | 19450615 | 19680930
|
| Today hail any size(1) | 19450615 | 19680930
| | | Today hail(0,4-7) | 19450615 | 19680930
|
| Visibility (old code) | 19450615 | 19680930
| | | Visibility (new code) | 19450615 | 19680930
|
| Today fog at 0900GMT (1) | 19450615 | 19680930
| | | Today gale force winds(1) | 19450615 | 19680930
|
| rainfall
|
| Rainfall 24h from 09GMT (ins) | 19450615 | 19680930
| | | Rainfall 24h from 09GMT (mm) | 19450615 | 19680930
|
| Rain day | 19450615 | 19680930
| | | Wet day | 19450615 | 19680930
|
| Very wet day | 19450615 | 19680930
|
| temperature counters
|
| Air frost, air min<0C | 19450615 | 19680930
| | | Ground frost, grass min<0C | 19450615 | 19680930
|
| Frost day, air max<0C | 19450615 | 19680930
| | | Warm day, air max>=25C | 19450615 | 19680930
|
| Hot day, air max>=30C | 19450615 | 19680930
| | | Warm night, air min>=15C | 19450615 | 19680930
|
| snow depth
|
| Total snow depth (cm) | 19450615 | 19680930
| | | Fresh snow depth (cm) | 19450615 | 19680930
|
| state of ground
|
| State of ground (2 digit code) | 19450615 | 19680930
| | | State of ground (1 digit code) | 19450615 | 19680930
|
| sunshine
|
| Sunshine duration (h) | 19450615 | 19680930
| | | Sunless day (0h) | 19450615 | 19680930
|
| Sunny day (12h) | 19450615 | 19680930
|