Altocumulus Average Cloud Amount (%) March, April, May (1954 - 1997) , Ship Observations Only Global Average: 16.6 Zonal Averages 17 zones Lat.N Average 85 11.5 75 12.5 65 15.6 55 14.4 45 14.9 35 16.2 25 13.9 15 12.3 5 19.0 -5 17.1 -15 15.5 -25 17.1 -35 17.7 -45 18.9 -55 20.7 -65 18.9 -75 15.0 Grid Box Averages 397 filled boxes Box # Lat.N Lon.E Average 1 85 60 15.4 2 85 180 9.3 3 85 300 9.5 4 75 20 17.4 5 75 60 13.8 6 75 100 6.4 7 75 140 12.6 8 75 180 7.6 9 75 220 10.8 10 75 260 17.8 11 75 300 15.9 12 75 340 12.5 13 65 10 20.0 14 65 30 14.7 15 65 50 13.0 16 65 70 8.1 21 65 170 8.5 22 65 190 9.6 23 65 210 13.5 27 65 290 13.4 29 65 330 17.7 30 65 350 18.4 31 55 10 15.8 32 55 30 16.8 37 55 130 10.8 38 55 150 8.9 39 55 170 11.5 40 55 190 13.1 41 55 210 14.9 42 55 230 14.3 44 55 270 21.8 45 55 290 10.2 46 55 310 13.9 47 55 330 17.9 48 55 350 17.8 49 45 5 15.2 50 45 15 14.6 51 45 25 12.2 52 45 35 9.7 53 45 45 11.9 54 45 55 9.5 61 45 125 9.6 62 45 135 8.8 63 45 145 9.3 64 45 155 10.6 65 45 165 12.6 66 45 175 14.0 67 45 185 16.0 68 45 195 16.2 69 45 205 16.7 70 45 215 16.6 71 45 225 15.6 72 45 235 14.2 77 45 285 13.2 78 45 295 13.7 79 45 305 14.5 80 45 315 16.6 81 45 325 18.1 82 45 335 18.8 83 45 345 16.6 84 45 355 16.0 85 35 5 14.7 86 35 15 12.6 87 35 25 10.8 88 35 35 9.3 89 35 45 9.3 90 35 55 12.2 96 35 115 6.6 97 35 125 14.1 98 35 135 14.7 99 35 145 13.3 100 35 155 15.0 101 35 165 16.9 102 35 175 17.5 103 35 185 20.1 104 35 195 19.9 105 35 205 19.8 106 35 215 19.8 107 35 225 16.4 108 35 235 11.5 109 35 245 8.3 112 35 275 13.1 113 35 285 15.8 114 35 295 16.4 115 35 305 16.9 116 35 315 17.8 117 35 325 17.6 118 35 335 17.7 119 35 345 14.2 120 35 355 12.9 124 25 35 5.2 125 25 45 11.2 126 25 55 7.1 127 25 65 4.2 128 25 75 4.3 129 25 85 9.8 130 25 95 11.7 131 25 105 19.0 132 25 115 19.5 133 25 125 17.6 134 25 135 15.5 135 25 145 14.6 136 25 155 13.7 137 25 165 13.6 138 25 175 13.0 139 25 185 13.4 140 25 195 13.4 141 25 205 14.0 142 25 215 17.3 143 25 225 20.7 144 25 235 18.0 145 25 245 12.2 146 25 255 10.3 147 25 265 15.2 148 25 275 12.4 149 25 285 13.2 150 25 295 12.8 151 25 305 12.8 152 25 315 13.7 153 25 325 13.0 154 25 335 11.5 155 25 345 8.0 156 25 355 9.2 160 15 35 5.9 161 15 45 6.8 162 15 55 4.0 163 15 65 3.7 164 15 75 7.1 165 15 85 9.0 166 15 95 9.1 167 15 105 14.0 168 15 115 8.6 169 15 125 9.7 170 15 135 9.1 171 15 145 9.1 172 15 155 10.2 173 15 165 11.8 174 15 175 11.9 175 15 185 12.6 176 15 195 15.6 177 15 205 16.5 178 15 215 19.8 179 15 225 25.1 180 15 235 24.5 181 15 245 15.8 182 15 255 9.7 183 15 265 10.8 184 15 275 12.2 185 15 285 11.9 186 15 295 11.3 187 15 305 11.5 188 15 315 13.6 189 15 325 12.9 190 15 335 10.7 191 15 345 8.3 193 5 5 23.8 197 5 45 7.1 198 5 55 7.8 199 5 65 8.6 200 5 75 14.1 201 5 85 20.4 202 5 95 27.3 203 5 105 16.3 204 5 115 16.2 205 5 125 16.9 206 5 135 19.7 207 5 145 19.4 208 5 155 21.8 209 5 165 23.1 210 5 175 21.0 211 5 185 21.0 212 5 195 21.7 213 5 205 22.5 214 5 215 19.7 215 5 225 19.5 216 5 235 16.6 217 5 245 17.5 218 5 255 14.9 219 5 265 18.3 220 5 275 23.8 221 5 285 22.4 222 5 295 13.1 223 5 305 17.0 224 5 315 23.5 225 5 325 21.1 226 5 335 18.6 227 5 345 18.6 228 5 355 22.6 229 -5 5 20.1 230 -5 15 18.1 232 -5 35 12.2 233 -5 45 11.8 234 -5 55 10.5 235 -5 65 14.9 236 -5 75 18.0 237 -5 85 23.1 238 -5 95 25.2 239 -5 105 26.0 240 -5 115 24.2 241 -5 125 20.4 242 -5 135 24.8 243 -5 145 29.1 244 -5 155 24.7 245 -5 165 23.2 246 -5 175 19.6 247 -5 185 16.8 248 -5 195 14.5 249 -5 205 10.1 250 -5 215 11.1 251 -5 225 9.0 252 -5 235 11.3 253 -5 245 13.2 254 -5 255 15.1 255 -5 265 15.8 256 -5 275 22.1 257 -5 285 22.9 260 -5 315 29.0 261 -5 325 19.3 262 -5 335 13.2 263 -5 345 10.7 264 -5 355 12.8 265 -15 5 13.6 266 -15 15 28.0 268 -15 35 9.9 269 -15 45 13.4 270 -15 55 13.5 271 -15 65 13.8 272 -15 75 15.0 273 -15 85 16.9 274 -15 95 18.9 275 -15 105 14.9 276 -15 115 11.2 277 -15 125 11.9 278 -15 135 19.8 279 -15 145 19.9 280 -15 155 18.2 281 -15 165 19.4 282 -15 175 22.2 283 -15 185 22.9 284 -15 195 19.2 285 -15 205 15.6 286 -15 215 11.6 287 -15 225 10.6 288 -15 235 11.4 289 -15 245 13.0 290 -15 255 15.7 291 -15 265 16.4 292 -15 275 17.3 293 -15 285 19.3 297 -15 325 15.7 298 -15 335 10.4 299 -15 345 11.6 300 -15 355 13.6 301 -25 5 12.5 302 -25 15 11.4 304 -25 35 10.7 305 -25 45 13.2 306 -25 55 16.6 307 -25 65 15.2 308 -25 75 16.2 309 -25 85 16.0 310 -25 95 18.6 311 -25 105 16.9 312 -25 115 12.4 315 -25 145 17.4 316 -25 155 14.0 317 -25 165 16.5 318 -25 175 19.7 319 -25 185 21.3 320 -25 195 24.0 321 -25 205 22.7 322 -25 215 20.1 323 -25 225 17.5 324 -25 235 16.6 325 -25 245 15.4 326 -25 255 18.1 327 -25 265 16.9 328 -25 275 15.3 329 -25 285 21.1 332 -25 315 21.2 333 -25 325 17.9 334 -25 335 16.6 335 -25 345 14.8 336 -25 355 16.4 337 -35 5 18.9 338 -35 15 11.8 339 -35 25 13.9 340 -35 35 13.3 341 -35 45 15.8 342 -35 55 18.8 343 -35 65 19.4 344 -35 75 18.1 345 -35 85 19.0 346 -35 95 20.1 347 -35 105 17.9 348 -35 115 16.6 349 -35 125 19.5 350 -35 135 19.9 351 -35 145 18.2 352 -35 155 16.0 353 -35 165 16.5 354 -35 175 17.0 355 -35 185 18.4 356 -35 195 18.7 357 -35 205 19.8 358 -35 215 21.3 359 -35 225 21.6 360 -35 235 20.5 361 -35 245 17.4 362 -35 255 17.7 363 -35 265 16.9 364 -35 275 14.8 365 -35 285 12.7 366 -35 295 17.6 367 -35 305 13.4 368 -35 315 17.6 369 -35 325 17.4 370 -35 335 17.0 371 -35 345 20.0 372 -35 355 19.7 373 -45 5 17.8 374 -45 15 25.8 375 -45 25 29.4 376 -45 35 24.0 377 -45 45 25.7 378 -45 55 18.6 379 -45 65 19.4 380 -45 75 17.8 381 -45 85 27.3 382 -45 95 22.1 383 -45 105 18.9 384 -45 115 18.4 385 -45 125 20.3 386 -45 135 22.7 387 -45 145 18.4 388 -45 155 17.5 389 -45 165 16.1 390 -45 175 16.3 391 -45 185 19.3 392 -45 195 18.5 393 -45 205 16.1 394 -45 215 17.0 395 -45 225 19.6 396 -45 235 22.2 397 -45 245 9.8 398 -45 255 11.4 399 -45 265 14.8 400 -45 275 12.0 401 -45 285 12.9 402 -45 295 13.6 403 -45 305 15.9 404 -45 315 18.0 405 -45 325 19.4 406 -45 335 14.2 407 -45 345 24.3 408 -45 355 18.8 409 -55 10 24.3 410 -55 30 21.9 411 -55 50 19.9 412 -55 70 20.4 413 -55 90 16.8 414 -55 110 19.1 415 -55 130 24.9 416 -55 150 20.8 417 -55 170 24.7 418 -55 190 21.1 419 -55 210 13.1 420 -55 230 14.1 421 -55 250 21.6 422 -55 270 17.4 423 -55 290 18.8 424 -55 310 24.6 425 -55 330 23.1 426 -55 350 25.4 427 -65 10 22.0 428 -65 30 20.1 429 -65 50 21.0 430 -65 70 13.7 431 -65 90 19.9 432 -65 110 22.8 433 -65 130 17.8 434 -65 150 16.7 435 -65 170 22.1 436 -65 190 14.8 437 -65 210 18.0 438 -65 230 15.8 439 -65 250 12.1 440 -65 270 19.3 441 -65 290 16.2 442 -65 310 31.2 443 -65 330 14.3 444 -65 350 23.0 449 -75 180 14.4 450 -75 220 13.8 451 -75 260 12.1 452 -75 300 13.6 453 -75 340 21.2