Total Cloud Cover Average Cloud Amount (%) April (1954 - 1997) , Ship Observations Only Global Average: 66.7 Zonal Averages 17 zones Lat.N Average 85 55.6 75 63.3 65 76.0 55 79.2 45 77.1 35 69.1 25 58.2 15 51.9 5 61.2 -5 58.0 -15 57.4 -25 62.3 -35 68.2 -45 78.9 -55 84.4 -65 88.6 -75 81.6 Grid Box Averages 386 filled boxes Box # Lat.N Lon.E Average 1 85 60 55.9 2 85 180 51.9 3 85 300 60.6 4 75 20 81.0 5 75 60 67.8 6 75 100 48.7 7 75 140 44.3 8 75 180 56.0 9 75 220 63.8 11 75 300 57.3 12 75 340 79.2 13 65 10 75.1 14 65 30 74.6 15 65 50 62.6 16 65 70 54.3 21 65 170 76.1 22 65 190 73.9 23 65 210 74.3 27 65 290 68.0 28 65 310 75.8 29 65 330 82.2 30 65 350 80.9 31 55 10 66.1 32 55 30 61.8 38 55 150 73.3 39 55 170 79.6 40 55 190 84.7 41 55 210 81.8 42 55 230 77.8 45 55 290 72.8 46 55 310 84.1 47 55 330 83.0 48 55 350 73.8 49 45 5 53.3 50 45 15 52.4 51 45 25 60.0 52 45 35 62.0 53 45 45 58.1 54 45 55 45.9 61 45 125 58.7 62 45 135 54.5 63 45 145 65.5 64 45 155 81.2 65 45 165 85.4 66 45 175 85.6 67 45 185 84.9 68 45 195 85.0 69 45 205 84.2 70 45 215 82.2 71 45 225 79.5 72 45 235 72.5 77 45 285 59.3 78 45 295 66.0 79 45 305 76.4 80 45 315 80.5 81 45 325 78.7 82 45 335 78.1 83 45 345 74.2 84 45 355 66.5 85 35 5 53.8 86 35 15 49.4 87 35 25 45.3 88 35 35 42.6 89 35 45 64.1 90 35 55 53.3 96 35 115 44.6 97 35 125 60.6 98 35 135 64.3 99 35 145 69.7 100 35 155 78.2 101 35 165 80.4 102 35 175 79.3 103 35 185 79.4 104 35 195 79.0 105 35 205 79.8 106 35 215 78.4 107 35 225 76.4 108 35 235 63.4 109 35 245 53.1 112 35 275 46.0 113 35 285 55.7 114 35 295 67.8 115 35 305 69.4 116 35 315 68.6 117 35 325 66.8 118 35 335 68.4 119 35 345 64.2 120 35 355 49.8 124 25 35 19.3 125 25 45 41.8 126 25 55 29.2 127 25 65 23.9 128 25 75 26.9 129 25 85 44.3 130 25 95 44.8 131 25 105 72.9 132 25 115 71.6 133 25 125 69.5 134 25 135 63.6 135 25 145 58.5 136 25 155 61.4 137 25 165 61.9 138 25 175 61.1 139 25 185 61.8 140 25 195 61.8 141 25 205 63.2 142 25 215 69.5 143 25 225 75.3 144 25 235 74.0 145 25 245 50.3 146 25 255 38.0 147 25 265 54.7 148 25 275 46.9 149 25 285 50.2 150 25 295 51.8 151 25 305 53.0 152 25 315 55.0 153 25 325 56.2 154 25 335 57.2 155 25 345 41.5 156 25 355 43.7 160 15 35 18.6 161 15 45 28.3 162 15 55 28.5 163 15 65 25.3 164 15 75 35.3 165 15 85 43.0 166 15 95 41.7 167 15 105 57.4 168 15 115 42.2 169 15 125 46.5 170 15 135 48.7 171 15 145 51.0 172 15 155 53.0 173 15 165 57.5 174 15 175 55.8 175 15 185 58.3 176 15 195 61.9 177 15 205 62.5 178 15 215 68.8 179 15 225 74.6 180 15 235 76.9 181 15 245 62.1 182 15 255 40.1 183 15 265 41.2 184 15 275 46.6 185 15 285 50.1 186 15 295 47.0 187 15 305 50.9 188 15 315 53.4 189 15 325 59.6 190 15 335 55.2 191 15 345 29.9 193 5 5 67.8 197 5 45 42.7 198 5 55 39.2 199 5 65 40.8 200 5 75 53.2 201 5 85 60.7 202 5 95 66.7 203 5 105 53.5 204 5 115 51.7 205 5 125 54.2 206 5 135 60.6 207 5 145 65.2 208 5 155 67.8 209 5 165 68.9 210 5 175 65.2 211 5 185 67.2 212 5 195 68.3 213 5 205 68.5 214 5 215 70.6 215 5 225 66.7 216 5 235 65.2 217 5 245 59.5 218 5 255 53.6 219 5 265 55.5 220 5 275 61.7 221 5 285 61.5 223 5 305 60.4 224 5 315 69.3 225 5 325 68.5 226 5 335 64.4 227 5 345 56.8 228 5 355 65.9 229 -5 5 65.0 230 -5 15 60.4 232 -5 35 55.6 233 -5 45 50.6 234 -5 55 48.3 235 -5 65 53.1 236 -5 75 58.3 237 -5 85 61.5 238 -5 95 66.4 239 -5 105 67.1 240 -5 115 60.5 241 -5 125 55.9 242 -5 135 63.8 243 -5 145 70.7 244 -5 155 69.5 245 -5 165 68.2 246 -5 175 62.7 247 -5 185 59.0 248 -5 195 54.9 249 -5 205 51.8 250 -5 215 52.2 251 -5 225 49.8 252 -5 235 49.9 253 -5 245 55.0 254 -5 255 55.8 255 -5 265 58.4 256 -5 275 56.5 257 -5 285 55.6 260 -5 315 71.2 261 -5 325 62.0 262 -5 335 56.9 263 -5 345 51.8 264 -5 355 58.3 265 -15 5 72.0 266 -15 15 65.4 268 -15 35 45.5 269 -15 45 51.8 270 -15 55 54.8 271 -15 65 56.0 272 -15 75 56.8 273 -15 85 63.1 274 -15 95 64.9 275 -15 105 55.9 276 -15 115 37.2 277 -15 125 39.2 278 -15 135 58.4 279 -15 145 62.8 280 -15 155 64.6 281 -15 165 62.1 282 -15 175 66.7 283 -15 185 65.7 284 -15 195 60.2 285 -15 205 57.0 286 -15 215 51.6 287 -15 225 49.6 288 -15 235 48.4 289 -15 245 50.2 290 -15 255 54.9 291 -15 265 64.0 292 -15 275 71.0 293 -15 285 58.9 297 -15 325 55.7 298 -15 335 49.4 299 -15 345 47.8 300 -15 355 65.0 301 -25 5 69.3 302 -25 15 53.3 304 -25 35 49.6 305 -25 45 54.9 306 -25 55 58.8 307 -25 65 61.4 308 -25 75 61.3 309 -25 85 63.8 310 -25 95 65.8 311 -25 105 64.0 312 -25 115 43.7 315 -25 145 57.6 316 -25 155 54.5 317 -25 165 58.9 318 -25 175 64.7 319 -25 185 66.9 320 -25 195 70.3 321 -25 205 70.8 322 -25 215 66.2 323 -25 225 61.4 324 -25 235 58.7 325 -25 245 55.9 326 -25 255 59.2 327 -25 265 68.3 328 -25 275 71.7 329 -25 285 76.5 332 -25 315 58.6 333 -25 325 56.6 334 -25 335 59.5 335 -25 345 57.9 336 -25 355 61.9 337 -35 5 73.0 338 -35 15 53.4 339 -35 25 54.3 340 -35 35 59.1 341 -35 45 63.0 342 -35 55 68.8 343 -35 65 69.7 344 -35 75 72.0 345 -35 85 73.3 346 -35 95 76.4 347 -35 105 72.7 348 -35 115 62.3 349 -35 125 69.8 350 -35 135 69.5 351 -35 145 63.1 352 -35 155 58.6 353 -35 165 65.9 354 -35 175 61.5 355 -35 185 67.2 356 -35 195 69.2 357 -35 205 72.8 358 -35 215 74.8 359 -35 225 74.4 360 -35 235 65.9 361 -35 245 73.9 362 -35 255 76.3 363 -35 265 71.5 364 -35 275 73.3 365 -35 285 61.8 367 -35 305 54.7 368 -35 315 62.6 369 -35 325 68.1 370 -35 335 70.6 371 -35 345 68.9 372 -35 355 71.4 373 -45 5 81.2 374 -45 15 78.5 375 -45 25 80.7 376 -45 35 81.3 377 -45 45 81.8 378 -45 55 81.5 379 -45 65 81.0 380 -45 75 81.4 381 -45 85 85.3 382 -45 95 85.1 383 -45 105 85.7 384 -45 115 84.6 385 -45 125 79.8 386 -45 135 79.8 387 -45 145 68.3 388 -45 155 71.0 389 -45 165 76.4 390 -45 175 63.2 391 -45 185 76.0 392 -45 195 78.1 393 -45 205 78.8 394 -45 215 80.6 395 -45 225 84.2 396 -45 235 85.4 397 -45 245 84.7 398 -45 255 78.6 399 -45 265 79.2 400 -45 275 83.3 401 -45 285 80.5 402 -45 295 60.6 403 -45 305 66.0 404 -45 315 74.8 405 -45 325 79.1 406 -45 335 80.1 407 -45 345 75.5 408 -45 355 77.6 409 -55 10 83.2 410 -55 30 85.8 411 -55 50 84.9 412 -55 70 86.6 413 -55 90 89.0 414 -55 110 86.2 415 -55 130 85.6 416 -55 150 84.4 417 -55 170 84.1 418 -55 190 87.6 419 -55 210 88.0 420 -55 230 83.9 421 -55 250 89.5 422 -55 270 83.7 423 -55 290 73.6 424 -55 310 78.7 425 -55 330 81.7 426 -55 350 81.2 427 -65 10 86.3 428 -65 30 90.4 429 -65 50 85.3 430 -65 70 88.9 431 -65 90 88.8 432 -65 110 90.4 433 -65 130 90.8 434 -65 150 85.8 435 -65 170 92.4 438 -65 230 96.1 440 -65 270 89.8 441 -65 290 82.0 442 -65 310 88.1 443 -65 330 86.6 444 -65 350 86.0 450 -75 220 81.6