| ISOTHERMS | Line joining points of the same temperature on meteorological maps |
| ISOBAR | Line connecting points of the same atmospheric pressure (6) |
| FORECAST | A prediction of the atmospheric conditions, based on meteorological observations; or, a calculation, estimation or prophecy generally (8) |
| ISOPLETH | A line joining points of equal temperature (8) |
| ISOTHERM | A line joining points of equal temperature (8) |
| ISALLOBAR | Line joining points of equal barometric pressure change during a set time (9) |
| ISOSEISMAL | Like a line joining points of equal earthquake strength |
| ISOHELS | Lines joining points of equal sunshine (7) |
| LEY | Line joining points in the landscape |
| AVOGADROSLAW | The principle that equal volumes of all gases contain the same number of molecules at the same temperature and pressure (9,3) |
| DIAGONAL | From the Greek for "through", a line joining non-adjacent vertices of a square or other polygon; a slanting row of squares of the same colour on a chessboard; or, the bias of cloth (8) |
| CONTOURS | Lines on a map joining points of equal height (8) |
| AVOGADRO | Amedeo ___ (1776-1856), Italian physicist whose eponymous law states that equal volumes of all gases at the same temperature and pressure contain equal numbers of molecules (8) |
| ISOTHERMAL | Short email about having the same temperature (10) |
| DOT | Cotton, say, needs the same temperature |
| CANVASS | Joining point of two conductors through which a current may pass |
| ISOBARS | Lines of equal atmospheric pressure on a meteorological map (7) |
| LEYLINES | Paths joining points in the landscape; thought to be routes of prehistoric tracks (3,5) |
| MERIDIAN | Any of the imaginary lines joining the north and south poles at right angles to the equator |
| CHORD | Straight line joining two points on a curve |
