The weather MPI has many parameters, here is the list of most of them available and the values they may hold.

Daytime: {weather:daytime}
Possible values - night, dawn, morning, afternoon, dusk

Ground: {weather:ground}
Possible values - dry, snowy, wet, icy

Last precipitation: {weather:last_precip}
Possible values - snow, rain, hail, sleet

Last precipitation time: {weather:last_ptime}
Possible values - a time.

Moon: {weather:moon}
Possible values - new/crescent/quarter/gibbous/full waxing/waning

Moon position: {weather:moonhr}
Possible values - 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16

Moon Status: {weather:moonstat}
Possible values - set, obscured, hidden, low, high, rising, setting

Precipitation rate: {weather:prate}
Possible values - 0, 1, 2, 3, 4

Precipitation status: {weather:precip}
Possible values - none, very light, light, steady, heavy

Season: {weather:season}
Possible values - spring, summer, fall, winter

Sky: {weather:sky}
Possible values - clear, overcast, cloudy, some_clouds

Temperature desc: {weather:temp}
Possible values - a number

Temp C: {weather:tempc}
Possible values - a number

Temp F: {weather:tempf}
Possible values - a number

Tide: {weather:tide}
Possible values - high_tide, low_tide, mid_tide

Watertable: {weather:watertable}
Possible values - flooded, high, normal, low, dry

Wind desc: {weather:wind}
Possible values - calm, breezy, gusty, windy, hi_wind

Wind Direction: {weather:winddir}
Possible values - north, east, south, west, northeast, southeast, northwest, southwest, north-Northeast, south-Northeast, east-Southeast, south-Southeast, south-Southwest, west-Southwest, west-Northwest, north-Northwest

Wind Speed: {weather:windspd}
Possible values - a number