Altocumulus Frequency of Occurrence (%) December, January, February (1954 - 1997) Night, Ship Observations Only Global Average: 34.4 Zonal Averages 17 zones Lat.N Average 85 22.1 75 20.0 65 22.3 55 21.9 45 25.3 35 30.3 25 29.9 15 28.2 5 39.5 -5 38.7 -15 39.2 -25 39.1 -35 36.0 -45 36.4 -55 39.0 -65 34.3 -75 34.2 Grid Box Averages 378 filled boxes Box # Lat.N Lon.E Average 1 85 60 26.9 2 85 180 14.9 3 85 300 25.9 4 75 20 23.6 5 75 60 15.6 7 75 140 12.2 8 75 180 20.1 9 75 220 23.0 12 75 340 26.6 13 65 10 29.6 14 65 30 26.3 15 65 50 18.6 21 65 170 8.1 22 65 190 7.7 23 65 210 14.2 29 65 330 22.8 30 65 350 29.9 31 55 10 22.9 32 55 30 25.8 38 55 150 14.4 39 55 170 22.2 40 55 190 22.6 41 55 210 23.6 42 55 230 22.7 46 55 310 16.9 47 55 330 25.6 48 55 350 25.9 49 45 5 30.6 50 45 15 26.4 51 45 25 20.5 52 45 35 17.6 53 45 45 22.7 54 45 55 18.1 62 45 135 12.8 63 45 145 17.9 64 45 155 23.8 65 45 165 27.1 66 45 175 27.2 67 45 185 26.3 68 45 195 29.3 69 45 205 28.3 70 45 215 30.1 71 45 225 26.6 72 45 235 25.3 77 45 285 15.9 78 45 295 19.3 79 45 305 20.9 80 45 315 22.8 81 45 325 27.2 82 45 335 28.7 83 45 345 26.7 84 45 355 26.5 85 35 5 30.4 86 35 15 27.4 87 35 25 27.1 88 35 35 27.8 96 35 115 6.7 97 35 125 22.7 98 35 135 24.5 99 35 145 24.2 100 35 155 32.3 101 35 165 29.9 102 35 175 31.3 103 35 185 32.1 104 35 195 31.9 105 35 205 32.4 106 35 215 34.9 107 35 225 30.4 108 35 235 25.0 109 35 245 19.6 112 35 275 33.5 113 35 285 29.9 114 35 295 31.9 115 35 305 33.7 116 35 315 33.6 117 35 325 33.3 118 35 335 34.5 119 35 345 29.2 120 35 355 26.8 124 25 35 13.2 125 25 45 24.8 126 25 55 16.3 127 25 65 11.4 128 25 75 5.5 129 25 85 18.0 130 25 95 10.2 132 25 115 28.5 133 25 125 32.3 134 25 135 35.2 135 25 145 37.1 136 25 155 31.3 137 25 165 30.4 138 25 175 30.2 139 25 185 31.0 140 25 195 28.4 141 25 205 28.3 142 25 215 33.8 143 25 225 38.1 144 25 235 36.4 145 25 245 27.5 146 25 255 28.4 147 25 265 35.5 148 25 275 35.3 149 25 285 30.0 150 25 295 26.8 151 25 305 26.5 152 25 315 28.1 153 25 325 28.9 154 25 335 23.1 155 25 345 18.2 160 15 35 16.5 161 15 45 13.2 162 15 55 13.7 163 15 65 13.7 164 15 75 12.9 165 15 85 20.5 166 15 95 21.8 167 15 105 25.3 168 15 115 29.2 169 15 125 31.4 170 15 135 35.7 171 15 145 35.4 172 15 155 25.8 173 15 165 20.6 174 15 175 23.8 175 15 185 30.5 176 15 195 30.9 177 15 205 29.9 178 15 215 36.9 179 15 225 41.5 180 15 235 42.7 181 15 245 38.3 182 15 255 25.9 183 15 265 22.0 184 15 275 34.5 185 15 285 23.8 186 15 295 24.5 187 15 305 25.4 188 15 315 29.5 189 15 325 31.0 190 15 335 27.6 191 15 345 21.9 193 5 5 35.2 197 5 45 19.0 198 5 55 23.8 199 5 65 23.0 200 5 75 27.5 201 5 85 40.6 202 5 95 48.6 203 5 105 40.0 204 5 115 41.8 205 5 125 45.9 206 5 135 54.3 207 5 145 46.7 208 5 155 46.3 209 5 165 40.5 210 5 175 47.9 211 5 185 46.3 212 5 195 38.3 213 5 205 35.8 214 5 215 34.9 215 5 225 41.0 216 5 235 45.5 217 5 245 43.1 218 5 255 36.8 219 5 265 36.8 220 5 275 44.3 221 5 285 40.1 223 5 305 36.7 224 5 315 43.8 225 5 325 42.9 226 5 335 38.1 227 5 345 26.4 228 5 355 31.4 229 -5 5 46.3 230 -5 15 38.5 232 -5 35 29.3 233 -5 45 25.5 234 -5 55 36.9 235 -5 65 43.5 236 -5 75 46.6 237 -5 85 49.0 238 -5 95 54.4 239 -5 105 55.9 240 -5 115 52.7 241 -5 125 48.0 242 -5 135 47.7 243 -5 145 53.5 244 -5 155 50.0 245 -5 165 47.1 246 -5 175 46.1 247 -5 185 43.7 248 -5 195 37.1 249 -5 205 30.1 250 -5 215 24.4 251 -5 225 18.5 252 -5 235 18.7 253 -5 245 26.4 254 -5 255 35.0 255 -5 265 38.8 256 -5 275 53.8 257 -5 285 41.2 260 -5 315 40.5 261 -5 325 31.8 262 -5 335 25.9 263 -5 345 27.5 264 -5 355 30.6 265 -15 5 41.2 266 -15 15 32.5 268 -15 35 33.9 269 -15 45 37.6 270 -15 55 37.4 271 -15 65 37.0 272 -15 75 40.0 273 -15 85 43.1 274 -15 95 48.8 275 -15 105 37.1 276 -15 115 33.8 277 -15 125 32.4 278 -15 135 41.8 279 -15 145 43.1 280 -15 155 38.3 281 -15 165 40.5 282 -15 175 49.4 283 -15 185 50.5 284 -15 195 51.0 285 -15 205 42.4 286 -15 215 33.1 287 -15 225 31.7 288 -15 235 31.7 289 -15 245 35.9 290 -15 255 39.4 291 -15 265 43.4 292 -15 275 43.1 293 -15 285 41.5 297 -15 325 35.5 298 -15 335 27.9 299 -15 345 33.3 300 -15 355 37.1 301 -25 5 34.7 302 -25 15 24.7 304 -25 35 29.3 305 -25 45 34.0 306 -25 55 37.7 307 -25 65 37.0 308 -25 75 40.7 309 -25 85 45.6 310 -25 95 49.8 311 -25 105 37.7 312 -25 115 28.3 315 -25 145 27.3 316 -25 155 33.3 317 -25 165 42.0 318 -25 175 47.8 319 -25 185 45.1 320 -25 195 46.1 321 -25 205 41.9 322 -25 215 37.1 323 -25 225 29.8 324 -25 235 37.1 325 -25 245 32.6 326 -25 255 41.3 327 -25 265 50.1 328 -25 275 38.2 329 -25 285 34.2 332 -25 315 45.7 333 -25 325 40.7 334 -25 335 36.5 335 -25 345 37.2 336 -25 355 39.3 337 -35 5 39.6 338 -35 15 25.7 339 -35 25 34.6 340 -35 35 34.4 341 -35 45 36.6 342 -35 55 31.8 343 -35 65 35.7 344 -35 75 39.1 345 -35 85 40.6 346 -35 95 45.2 347 -35 105 38.3 348 -35 115 30.2 349 -35 125 37.5 350 -35 135 37.5 351 -35 145 32.4 352 -35 155 36.0 353 -35 165 39.8 354 -35 175 41.7 355 -35 185 44.8 356 -35 195 41.5 357 -35 205 42.0 358 -35 215 34.3 359 -35 225 30.6 360 -35 235 37.2 361 -35 245 33.3 362 -35 255 37.7 363 -35 265 26.8 364 -35 275 26.3 365 -35 285 22.7 367 -35 305 32.9 368 -35 315 31.8 369 -35 325 33.8 370 -35 335 36.6 371 -35 345 40.7 372 -35 355 41.4 373 -45 5 37.0 374 -45 15 35.7 375 -45 25 39.8 376 -45 35 40.7 377 -45 45 29.1 378 -45 55 33.1 379 -45 65 40.1 380 -45 75 36.6 381 -45 85 35.6 382 -45 95 39.0 383 -45 105 43.3 384 -45 115 40.3 385 -45 125 37.5 386 -45 135 40.1 387 -45 145 39.7 388 -45 155 40.6 389 -45 165 38.4 390 -45 175 39.7 391 -45 185 39.5 392 -45 195 38.9 393 -45 205 35.6 394 -45 215 31.6 399 -45 265 29.5 400 -45 275 25.7 401 -45 285 30.9 402 -45 295 30.7 403 -45 305 36.4 404 -45 315 35.3 405 -45 325 35.1 406 -45 335 34.5 407 -45 345 35.6 408 -45 355 36.5 409 -55 10 38.6 410 -55 30 37.6 411 -55 50 40.2 412 -55 70 39.8 413 -55 90 39.3 414 -55 110 38.7 415 -55 130 36.2 416 -55 150 31.5 417 -55 170 37.3 418 -55 190 46.8 419 -55 210 44.3 420 -55 230 35.1 421 -55 250 38.8 422 -55 270 38.8 423 -55 290 42.5 424 -55 310 41.2 425 -55 330 37.8 426 -55 350 38.6 427 -65 10 35.6 428 -65 30 54.2 429 -65 50 39.4 430 -65 70 30.0 431 -65 90 33.7 432 -65 110 27.6 433 -65 130 28.1 434 -65 150 30.7 435 -65 170 30.4 436 -65 190 34.6 437 -65 210 33.2 438 -65 230 26.2 439 -65 250 30.0 440 -65 270 35.1 441 -65 290 38.0 442 -65 310 47.0 443 -65 330 27.6 444 -65 350 33.1 449 -75 180 36.8 450 -75 220 31.8 451 -75 260 33.3 452 -75 300 35.0 453 -75 340 33.1