Altocumulus Frequency of Occurrence (%) September (1954 - 1997) Night, Ship Observations Only Global Average: 34.0 Zonal Averages 15 zones Lat.N Average 85 27.7 75 27.7 65 34.6 55 32.7 45 34.0 35 32.4 25 32.0 15 37.3 5 43.4 -5 33.4 -15 33.1 -25 34.0 -35 33.0 -45 31.4 -55 29.7 Grid Box Averages 312 filled boxes Box # Lat.N Lon.E Average 1 85 60 32.9 2 85 180 21.5 3 85 300 29.6 4 75 20 37.6 5 75 60 33.6 6 75 100 27.9 7 75 140 17.3 8 75 180 20.0 9 75 220 24.7 10 75 260 33.7 11 75 300 31.0 12 75 340 29.7 13 65 10 40.0 14 65 30 32.4 15 65 50 27.9 21 65 170 22.8 22 65 190 32.7 23 65 210 40.1 25 65 250 52.3 26 65 270 35.5 27 65 290 34.6 28 65 310 32.0 29 65 330 34.9 30 65 350 35.6 31 55 10 38.6 32 55 30 35.1 38 55 150 21.1 39 55 170 29.8 40 55 190 38.5 41 55 210 33.5 42 55 230 32.8 44 55 270 42.8 45 55 290 33.1 46 55 310 31.8 47 55 330 31.0 48 55 350 36.2 49 45 5 30.9 50 45 15 25.3 51 45 25 24.7 52 45 35 14.0 54 45 55 13.7 62 45 135 20.4 63 45 145 23.2 64 45 155 32.0 65 45 165 36.6 66 45 175 41.5 67 45 185 44.1 68 45 195 41.9 69 45 205 39.4 70 45 215 41.8 71 45 225 34.4 72 45 235 24.9 77 45 285 28.5 78 45 295 26.1 79 45 305 30.3 80 45 315 32.6 81 45 325 34.1 82 45 335 32.7 83 45 345 33.6 84 45 355 35.1 85 35 5 28.0 86 35 15 18.8 87 35 25 7.8 88 35 35 5.8 97 35 125 31.5 98 35 135 40.6 99 35 145 41.2 100 35 155 37.3 101 35 165 34.3 102 35 175 36.9 103 35 185 42.9 104 35 195 38.8 105 35 205 40.0 106 35 215 38.7 107 35 225 29.2 108 35 235 23.2 109 35 245 20.6 112 35 275 37.6 113 35 285 33.6 114 35 295 30.9 115 35 305 30.2 116 35 315 30.9 117 35 325 31.4 118 35 335 32.4 119 35 345 26.3 120 35 355 27.1 124 25 35 15.7 125 25 45 4.1 126 25 55 7.7 127 25 65 17.7 129 25 85 58.3 132 25 115 36.4 133 25 125 33.2 134 25 135 40.6 135 25 145 38.3 136 25 155 30.3 137 25 165 32.7 138 25 175 32.3 139 25 185 33.5 140 25 195 30.5 141 25 205 30.7 142 25 215 35.3 143 25 225 37.0 144 25 235 37.1 145 25 245 25.6 146 25 255 36.5 147 25 265 37.9 148 25 275 42.9 149 25 285 38.2 150 25 295 29.2 151 25 305 27.9 152 25 315 27.2 153 25 325 28.4 154 25 335 26.4 155 25 345 19.1 160 15 35 32.7 161 15 45 28.0 162 15 55 18.3 163 15 65 30.7 164 15 75 38.4 165 15 85 40.2 166 15 95 54.9 167 15 105 40.3 168 15 115 37.1 169 15 125 40.6 170 15 135 43.3 171 15 145 46.1 172 15 155 39.8 173 15 165 31.8 174 15 175 35.0 175 15 185 39.6 176 15 195 31.3 177 15 205 36.7 178 15 215 41.6 179 15 225 41.3 180 15 235 35.5 181 15 245 37.2 182 15 255 48.1 183 15 265 53.6 184 15 275 49.0 185 15 285 34.3 186 15 295 28.1 187 15 305 28.1 188 15 315 32.9 189 15 325 36.4 190 15 335 31.4 191 15 345 33.6 193 5 5 58.2 197 5 45 17.7 198 5 55 20.6 199 5 65 28.6 200 5 75 39.4 201 5 85 47.7 202 5 95 57.8 203 5 105 42.9 204 5 115 45.0 205 5 125 46.2 206 5 135 45.7 207 5 145 50.9 208 5 155 45.0 209 5 165 42.0 210 5 175 44.8 211 5 185 41.7 212 5 195 40.3 213 5 205 36.2 214 5 215 39.8 215 5 225 42.0 216 5 235 39.3 217 5 245 49.4 218 5 255 49.4 219 5 265 52.8 220 5 275 60.6 221 5 285 54.0 223 5 305 36.6 224 5 315 36.4 225 5 325 35.5 226 5 335 45.7 227 5 345 49.0 228 5 355 47.6 229 -5 5 46.3 230 -5 15 30.2 233 -5 45 22.6 234 -5 55 34.0 235 -5 65 40.0 236 -5 75 40.7 237 -5 85 52.2 238 -5 95 51.1 239 -5 105 36.0 240 -5 115 21.3 241 -5 125 26.7 242 -5 135 30.5 243 -5 145 46.8 244 -5 155 47.7 245 -5 165 41.5 246 -5 175 39.7 247 -5 185 32.3 248 -5 195 29.6 249 -5 205 26.0 250 -5 215 24.3 251 -5 225 19.4 252 -5 235 16.7 253 -5 245 24.6 254 -5 255 37.8 255 -5 265 38.0 256 -5 275 38.6 260 -5 315 25.9 261 -5 325 22.8 262 -5 335 23.3 263 -5 345 27.0 264 -5 355 31.0 265 -15 5 35.0 266 -15 15 40.0 268 -15 35 9.6 269 -15 45 16.1 270 -15 55 33.7 271 -15 65 40.5 272 -15 75 37.4 273 -15 85 43.8 274 -15 95 48.6 275 -15 105 30.9 276 -15 115 12.8 277 -15 125 10.5 278 -15 135 13.3 279 -15 145 23.4 280 -15 155 32.5 281 -15 165 35.7 282 -15 175 45.3 283 -15 185 44.8 284 -15 195 37.0 285 -15 205 26.9 286 -15 215 26.3 287 -15 225 20.7 288 -15 235 32.6 289 -15 245 37.4 290 -15 255 40.8 291 -15 265 40.9 292 -15 275 25.2 293 -15 285 19.1 297 -15 325 33.9 298 -15 335 35.7 299 -15 345 39.7 300 -15 355 35.1 301 -25 5 32.1 302 -25 15 24.1 304 -25 35 18.4 305 -25 45 23.9 306 -25 55 29.5 307 -25 65 41.8 308 -25 75 39.5 309 -25 85 43.9 310 -25 95 41.9 311 -25 105 33.2 312 -25 115 19.7 316 -25 155 23.7 317 -25 165 33.7 318 -25 175 36.9 319 -25 185 40.0 320 -25 195 34.9 321 -25 205 38.5 322 -25 215 31.4 323 -25 225 34.2 324 -25 235 37.1 325 -25 245 37.9 328 -25 275 20.8 329 -25 285 19.1 332 -25 315 42.9 333 -25 325 37.5 334 -25 335 36.4 335 -25 345 34.4 336 -25 355 43.4 337 -35 5 43.2 338 -35 15 28.1 339 -35 25 27.9 340 -35 35 28.2 341 -35 45 32.7 342 -35 55 30.7 343 -35 65 34.2 344 -35 75 26.3 345 -35 85 34.0 346 -35 95 40.1 347 -35 105 40.5 348 -35 115 30.0 349 -35 125 33.9 350 -35 135 35.1 351 -35 145 31.5 352 -35 155 31.9 353 -35 165 30.4 354 -35 175 36.9 355 -35 185 37.9 356 -35 195 33.1 357 -35 205 33.3 358 -35 215 28.5 364 -35 275 24.5 365 -35 285 25.5 367 -35 305 31.8 368 -35 315 29.5 369 -35 325 27.3 370 -35 335 39.3 371 -35 345 39.7 372 -35 355 39.8 387 -45 145 21.5 388 -45 155 35.7 389 -45 165 31.2 390 -45 175 28.8 391 -45 185 41.6 401 -45 285 25.7 402 -45 295 37.6 403 -45 305 28.1 417 -55 170 28.0 423 -55 290 24.5 424 -55 310 35.1 425 -55 330 30.5