Altocumulus Frequency of Occurrence (%) May (1954 - 1997) Night, Ship Observations Only Global Average: 32.5 Zonal Averages 16 zones Lat.N Average 85 20.5 75 24.2 65 33.8 55 31.2 45 32.4 35 33.0 25 32.6 15 32.5 5 44.2 -5 33.9 -15 32.8 -25 34.3 -35 31.7 -45 22.5 -55 25.6 -65 38.9 Grid Box Averages 316 filled boxes Box # Lat.N Lon.E Average 1 85 60 33.5 2 85 180 10.8 3 85 300 16.8 4 75 20 36.5 5 75 60 30.1 7 75 140 19.9 8 75 180 8.0 9 75 220 14.3 11 75 300 47.0 12 75 340 33.9 13 65 10 41.3 14 65 30 31.3 15 65 50 31.3 20 65 150 22.6 21 65 170 21.3 22 65 190 25.1 23 65 210 33.4 28 65 310 27.9 29 65 330 35.8 30 65 350 39.8 31 55 10 32.1 32 55 30 31.4 38 55 150 21.9 39 55 170 26.4 40 55 190 35.0 41 55 210 34.1 42 55 230 34.1 46 55 310 26.6 47 55 330 33.8 48 55 350 38.1 49 45 5 34.6 50 45 15 33.5 51 45 25 24.4 52 45 35 16.4 53 45 45 20.0 54 45 55 17.1 62 45 135 21.4 63 45 145 23.7 64 45 155 24.6 65 45 165 26.5 66 45 175 32.7 67 45 185 36.8 68 45 195 38.3 69 45 205 38.1 70 45 215 39.6 71 45 225 34.0 72 45 235 27.3 77 45 285 30.2 78 45 295 31.8 79 45 305 31.4 80 45 315 29.8 81 45 325 33.4 82 45 335 37.9 83 45 345 36.0 84 45 355 36.9 85 35 5 30.4 86 35 15 26.1 87 35 25 20.9 88 35 35 18.2 97 35 125 28.8 98 35 135 29.3 99 35 145 29.2 100 35 155 28.9 101 35 165 34.0 102 35 175 35.3 103 35 185 42.5 104 35 195 42.5 105 35 205 40.8 106 35 215 41.0 107 35 225 32.1 108 35 235 23.9 109 35 245 16.2 112 35 275 27.4 113 35 285 32.9 114 35 295 32.3 115 35 305 32.8 116 35 315 33.0 117 35 325 33.5 118 35 335 35.5 119 35 345 32.6 120 35 355 31.0 124 25 35 11.0 125 25 45 18.1 126 25 55 7.9 127 25 65 9.7 129 25 85 42.0 132 25 115 35.6 133 25 125 38.8 134 25 135 41.4 135 25 145 38.3 136 25 155 31.5 137 25 165 32.6 138 25 175 33.7 139 25 185 34.7 140 25 195 33.3 141 25 205 31.8 142 25 215 36.5 143 25 225 40.1 144 25 235 36.4 145 25 245 28.8 146 25 255 25.6 147 25 265 31.5 148 25 275 30.9 149 25 285 35.3 150 25 295 34.3 151 25 305 31.9 152 25 315 32.7 153 25 325 29.8 154 25 335 26.8 155 25 345 22.4 160 15 35 13.5 161 15 45 18.8 162 15 55 12.0 163 15 65 15.3 164 15 75 26.4 165 15 85 33.1 166 15 95 36.4 167 15 105 38.0 168 15 115 27.2 169 15 125 32.5 170 15 135 32.9 171 15 145 33.3 172 15 155 26.1 173 15 165 28.1 174 15 175 33.0 175 15 185 33.9 176 15 195 36.3 177 15 205 37.4 178 15 215 46.6 179 15 225 54.7 180 15 235 44.3 181 15 245 32.6 182 15 255 29.6 183 15 265 37.0 184 15 275 39.8 185 15 285 37.1 186 15 295 33.3 187 15 305 30.2 188 15 315 32.8 189 15 325 28.4 190 15 335 23.1 191 15 345 21.4 193 5 5 51.0 197 5 45 23.9 198 5 55 24.1 199 5 65 27.5 200 5 75 37.2 201 5 85 44.5 202 5 95 55.0 203 5 105 37.1 204 5 115 39.5 205 5 125 48.0 206 5 135 51.2 207 5 145 51.0 208 5 155 49.3 209 5 165 45.6 210 5 175 45.6 211 5 185 46.6 212 5 195 43.5 213 5 205 48.1 214 5 215 44.9 215 5 225 47.1 216 5 235 40.6 217 5 245 52.3 218 5 255 41.2 219 5 265 49.6 220 5 275 59.3 221 5 285 53.0 223 5 305 39.3 224 5 315 43.8 225 5 325 41.7 226 5 335 38.6 227 5 345 39.8 228 5 355 48.7 229 -5 5 37.2 230 -5 15 21.5 233 -5 45 30.3 234 -5 55 27.0 235 -5 65 27.3 236 -5 75 37.6 237 -5 85 46.4 238 -5 95 50.3 239 -5 105 43.8 240 -5 115 38.2 241 -5 125 38.8 242 -5 135 40.2 243 -5 145 51.2 244 -5 155 48.5 245 -5 165 39.7 246 -5 175 43.7 247 -5 185 35.6 248 -5 195 24.9 249 -5 205 24.9 250 -5 215 25.9 251 -5 225 21.0 252 -5 235 24.4 253 -5 245 22.4 254 -5 255 29.4 255 -5 265 32.8 256 -5 275 43.9 260 -5 315 46.9 261 -5 325 37.0 262 -5 335 26.1 263 -5 345 25.4 264 -5 355 29.3 265 -15 5 23.4 266 -15 15 33.3 268 -15 35 21.4 269 -15 45 23.8 270 -15 55 32.4 271 -15 65 31.6 272 -15 75 28.1 273 -15 85 35.8 274 -15 95 44.8 275 -15 105 36.5 276 -15 115 23.5 277 -15 125 19.1 278 -15 135 30.4 279 -15 145 34.8 280 -15 155 37.1 281 -15 165 38.5 282 -15 175 39.0 283 -15 185 45.2 284 -15 195 40.2 285 -15 205 33.5 286 -15 215 26.4 287 -15 225 26.5 288 -15 235 28.9 289 -15 245 23.6 290 -15 255 32.7 291 -15 265 38.7 292 -15 275 40.0 293 -15 285 39.0 297 -15 325 36.3 298 -15 335 27.7 299 -15 345 33.4 300 -15 355 28.7 301 -25 5 25.7 302 -25 15 19.8 304 -25 35 20.1 305 -25 45 29.0 306 -25 55 36.2 307 -25 65 31.7 308 -25 75 32.3 309 -25 85 38.0 310 -25 95 40.8 311 -25 105 35.4 312 -25 115 26.1 316 -25 155 30.8 317 -25 165 37.3 318 -25 175 39.1 319 -25 185 45.0 320 -25 195 39.3 321 -25 205 39.4 322 -25 215 34.0 323 -25 225 36.8 324 -25 235 38.9 325 -25 245 32.7 326 -25 255 33.5 327 -25 265 34.2 328 -25 275 29.6 329 -25 285 26.8 332 -25 315 43.2 333 -25 325 38.7 334 -25 335 36.2 335 -25 345 30.0 336 -25 355 32.1 337 -35 5 38.5 338 -35 15 25.3 339 -35 25 25.3 340 -35 35 23.8 341 -35 45 31.1 342 -35 55 41.0 343 -35 65 34.4 344 -35 75 28.6 345 -35 85 30.1 346 -35 95 29.4 347 -35 105 31.2 348 -35 115 31.3 349 -35 125 33.8 350 -35 135 36.9 351 -35 145 41.0 352 -35 155 32.9 353 -35 165 30.3 354 -35 175 29.6 355 -35 185 32.7 356 -35 195 35.0 357 -35 205 30.7 358 -35 215 36.4 359 -35 225 29.7 364 -35 275 34.8 365 -35 285 16.5 367 -35 305 30.6 368 -35 315 35.1 369 -35 325 34.4 370 -35 335 27.3 371 -35 345 30.6 372 -35 355 38.3 387 -45 145 34.1 388 -45 155 23.9 389 -45 165 24.0 390 -45 175 23.9 391 -45 185 22.1 397 -45 245 20.1 398 -45 255 13.0 399 -45 265 17.5 400 -45 275 18.9 401 -45 285 20.1 402 -45 295 28.5 403 -45 305 25.1 404 -45 315 24.0 417 -55 170 26.4 423 -55 290 24.5 424 -55 310 27.6 425 -55 330 23.7 442 -65 310 38.9