| Page 1 | A/D converter | | aberwind |
| Page 2 | ABI | | Abrolhos squalls |
| Page 3 | abscissa | | absolute instability |
| Page 4 | absolute instrument | | absolute refractive index |
| Page 5 | absolute stability | | absorbed solar radiation |
| Page 6 | absorptance | | absorption |
| Page 7 | absorptivity | | accessory cloud |
| Page 8 | acclimation | | accumulation zone |
| Page 9 | accumulation | | acicular ice |
| Page 10 | acid deposition | | acid snow |
| Page 11 | acidity of water | | acoustic imaging |
| Page 12 | acoustic impedance | | acoustic refraction |
| Page 13 | acoustic resonance | | acoustic transponder |
| Page 14 | acoustic velocimeter | | actinograph |
| Page 15 | actinometer | | active network |
| Page 16 | active nitrogen | | actual pressure |
| Page 17 | actual time of observation | | adfreezing |
| Page 18 | adhesion efficiency | | adiabatic diagram |
| Page 19 | adiabatic equilibrium | | adiabatic temperature gradient |
| Page 20 | adiabatic trial | | admissible concentration limit |
| Page 21 | adret | | advection frost |
| Page 22 | advection | | advisory forecast |
| Page 23 | advisory | | aerobiology |
| Page 24 | aerodrome elevation | | aerodynamically rough surface |
| Page 25 | aerodynamically smooth surface | | aerological station |
| Page 26 | aerological table | | aerosol size distribution |
| Page 27 | aerosol | | afterheat |
| Page 28 | afternoon effect | | agnostic chart |
| Page 29 | agonic line | | agrometeorological station |
| Page 30 | agrometeorology | | air–earth current |
| Page 31 | air freezing index | | air pocket |
| Page 32 | air poise | | air report |
| Page 33 | air resistance | | airborne expendable bathythermograph |
| Page 34 | airborne fraction | | aircraft observation |
| Page 35 | aircraft report | | airglow |
| Page 36 | airlight formula | | airmass thunderstorm |
| Page 37 | airplane observation | | airways observation |
| Page 38 | airways shelter | | Alberta clipper |
| Page 39 | Alberta low | | algorithm |
| Page 40 | aliasing | | alkynes |
| Page 41 | All-hallown summer | | alluvial |
| Page 42 | almanac | | alpenglow |
| Page 43 | alpha particle | | alti-electrograph |
| Page 44 | altigraph | | altocumulus castellanus |
| Page 45 | altocumulus duplicatus | | altocumulus translucidus |
| Page 46 | altocumulus undulatus | | ambient air |
| Page 47 | ambient pressure | | amorphous clouds |
| Page 48 | amorphous frost | | amplitude |
| Page 49 | AMSU | | anallobaric center |
| Page 50 | anallobaric | | analyzed chart |
| Page 51 | analyzed map | | anemoscope |
| Page 52 | anemovane | | angle of elevation |
| Page 53 | angle of incidence | | angstrom |
| Page 54 | angular drift | | angular wavenumber |
| Page 55 | angularity correction | | annual maximum series |
| Page 56 | annual minimum series | | anomaly correlation |
| Page 57 | anomaly of geopotential difference | | antarctic convergence |
| Page 58 | antarctic divergence | | antarctic stratospheric vortex |
| Page 59 | Antarctic Surface Water | | antenna temperature |
| Page 60 | antenna | | anti-mountain wind |
| Page 61 | anti-sea breeze | | anticyclonic circulation |
| Page 62 | anticyclonic phase | | antipleion |
| Page 63 | antiproton | | apaapaa |
| Page 64 | aperiodic | | apogean tide |
| Page 65 | apogean winds | | applied climatology |
| Page 66 | applied hydrology | | aquifer system |
| Page 67 | aquifer test | | arc cloud |
| Page 68 | arc discharge | | Arctic Circle |
| Page 69 | arctic climate | | arctic sea smoke |
| Page 70 | arctic stratospheric vortex | | area forecast |
| Page 71 | area of high pressure | | arid climate |
| Page 72 | arid-zone hydrology | | Arrhenius equation |
| Page 73 | Arrhenius expression | | artificial horizon |
| Page 74 | artificial ice nucleus | | aspect ratio |
| Page 75 | aspect | | Assmann psychrometer |
| Page 76 | astronomical horizon | | asymptotic expansion |
| Page 77 | asynchronous communication | | atmosphere–ocean interaction |
| Page 78 | atmosphere | | atmospheric dust |
| Page 79 | atmospheric dynamics | | atmospheric oscillation |
| Page 80 | atmospheric ozone | | atmospheric region |
| Page 81 | atmospheric science | | atmospheric wave |
| Page 82 | atmospheric window | | attractor |
| Page 83 | audibility zone | | auroral bands |
| Page 84 | auroral corona | | Australasian Mediterranean Water |
| Page 85 | austru | | autocorrelation |
| Page 86 | autogenous electrification | | autoregressive process |
| Page 87 | autoregressive series | | auxiliary thermometer |
| Page 88 | available head | | average drag coefficient |
| Page 89 | average interstitial velocity | | aviation forecast |
| Page 90 | aviation meteorology | | axial symmetry |
| Page 91 | axis of anticyclone | | ayalas |
| Page 92 | aygalas | | Azores high |