Total Cloud Cover Average Cloud Amount (%) April (1954 - 1997) Day, Ship Observations Only Global Average: 66.5 Zonal Averages 17 zones Lat.N Average 85 55.7 75 62.8 65 76.0 55 78.8 45 76.8 35 68.7 25 57.2 15 51.5 5 61.6 -5 58.0 -15 57.0 -25 61.7 -35 68.2 -45 78.8 -55 84.6 -65 88.4 -75 80.3 Grid Box Averages 381 filled boxes Box # Lat.N Lon.E Average 1 85 60 55.5 2 85 180 51.6 3 85 300 62.1 4 75 20 80.4 5 75 60 65.4 6 75 100 44.9 7 75 140 44.7 8 75 180 57.0 9 75 220 64.5 11 75 300 57.1 12 75 340 78.3 13 65 10 74.6 14 65 30 73.3 15 65 50 62.6 21 65 170 74.3 22 65 190 74.3 23 65 210 75.5 27 65 290 69.1 28 65 310 75.0 29 65 330 82.0 30 65 350 80.2 31 55 10 65.8 32 55 30 61.2 38 55 150 74.2 39 55 170 78.8 40 55 190 84.2 41 55 210 81.5 42 55 230 78.8 45 55 290 72.8 46 55 310 82.9 47 55 330 82.5 48 55 350 73.3 49 45 5 54.4 50 45 15 53.0 51 45 25 58.8 52 45 35 62.5 53 45 45 61.6 54 45 55 54.0 61 45 125 61.5 62 45 135 57.6 63 45 145 68.5 64 45 155 80.9 65 45 165 84.9 66 45 175 84.5 67 45 185 83.9 68 45 195 84.5 69 45 205 83.0 70 45 215 82.0 71 45 225 79.5 72 45 235 72.5 77 45 285 59.0 78 45 295 65.9 79 45 305 76.0 80 45 315 80.4 81 45 325 78.3 82 45 335 76.6 83 45 345 72.5 84 45 355 65.5 85 35 5 53.6 86 35 15 50.2 87 35 25 46.6 88 35 35 44.4 89 35 45 63.3 90 35 55 54.9 96 35 115 47.1 97 35 125 61.5 98 35 135 65.3 99 35 145 70.8 100 35 155 77.8 101 35 165 79.2 102 35 175 77.5 103 35 185 77.2 104 35 195 78.1 105 35 205 77.8 106 35 215 77.3 107 35 225 75.3 108 35 235 63.2 109 35 245 53.6 112 35 275 48.3 113 35 285 56.2 114 35 295 67.0 115 35 305 69.3 116 35 315 68.5 117 35 325 66.7 118 35 335 68.1 119 35 345 62.7 120 35 355 49.5 124 25 35 20.6 125 25 45 43.9 126 25 55 30.9 127 25 65 24.0 128 25 75 26.9 129 25 85 42.3 130 25 95 41.8 131 25 105 73.5 132 25 115 73.6 133 25 125 69.6 134 25 135 63.6 135 25 145 57.8 136 25 155 59.6 137 25 165 58.1 138 25 175 58.6 139 25 185 60.2 140 25 195 60.1 141 25 205 61.1 142 25 215 67.9 143 25 225 73.5 144 25 235 72.0 145 25 245 50.2 146 25 255 38.4 147 25 265 54.7 148 25 275 47.3 149 25 285 50.2 150 25 295 52.1 151 25 305 53.8 152 25 315 55.1 153 25 325 55.3 154 25 335 55.5 155 25 345 39.3 160 15 35 19.3 161 15 45 28.6 162 15 55 29.1 163 15 65 26.0 164 15 75 35.1 165 15 85 41.8 166 15 95 40.5 167 15 105 59.4 168 15 115 44.4 169 15 125 47.0 170 15 135 48.4 171 15 145 50.1 172 15 155 52.4 173 15 165 57.4 174 15 175 55.0 175 15 185 57.6 176 15 195 60.2 177 15 205 60.5 178 15 215 67.0 179 15 225 73.3 180 15 235 75.8 181 15 245 62.3 182 15 255 39.9 183 15 265 39.6 184 15 275 45.6 185 15 285 51.4 186 15 295 48.7 187 15 305 51.5 188 15 315 52.7 189 15 325 57.3 190 15 335 54.6 191 15 345 31.0 193 5 5 68.3 197 5 45 43.0 198 5 55 40.3 199 5 65 42.9 200 5 75 53.8 201 5 85 61.6 202 5 95 66.7 203 5 105 56.0 204 5 115 54.0 205 5 125 56.2 206 5 135 61.0 207 5 145 65.0 208 5 155 67.3 209 5 165 69.3 210 5 175 66.2 211 5 185 67.7 212 5 195 66.8 213 5 205 67.1 214 5 215 68.5 215 5 225 65.4 216 5 235 64.8 217 5 245 63.0 218 5 255 54.4 219 5 265 54.8 220 5 275 60.8 221 5 285 64.6 223 5 305 61.1 224 5 315 68.3 225 5 325 68.7 226 5 335 64.6 227 5 345 59.3 228 5 355 66.7 229 -5 5 63.9 230 -5 15 66.5 232 -5 35 61.5 233 -5 45 51.2 234 -5 55 49.0 235 -5 65 53.5 236 -5 75 59.4 237 -5 85 63.3 238 -5 95 66.9 239 -5 105 68.9 240 -5 115 63.4 241 -5 125 56.1 242 -5 135 64.8 243 -5 145 71.7 244 -5 155 68.8 245 -5 165 67.5 246 -5 175 63.1 247 -5 185 58.1 248 -5 195 56.1 249 -5 205 52.6 250 -5 215 51.3 251 -5 225 50.3 252 -5 235 49.6 253 -5 245 53.7 254 -5 255 54.5 255 -5 265 56.0 256 -5 275 50.1 257 -5 285 56.6 260 -5 315 71.3 261 -5 325 62.6 262 -5 335 57.2 263 -5 345 53.0 264 -5 355 57.7 265 -15 5 66.7 266 -15 15 64.7 268 -15 35 47.5 269 -15 45 53.0 270 -15 55 54.3 271 -15 65 55.5 272 -15 75 58.3 273 -15 85 62.5 274 -15 95 64.8 275 -15 105 57.5 276 -15 115 40.5 277 -15 125 42.1 278 -15 135 60.7 279 -15 145 62.8 280 -15 155 63.8 281 -15 165 63.7 282 -15 175 66.1 283 -15 185 67.3 284 -15 195 62.8 285 -15 205 58.8 286 -15 215 52.3 287 -15 225 48.6 288 -15 235 48.4 289 -15 245 49.0 290 -15 255 53.0 291 -15 265 57.6 292 -15 275 64.8 293 -15 285 60.8 297 -15 325 55.9 298 -15 335 48.8 299 -15 345 46.8 300 -15 355 59.6 301 -25 5 63.9 302 -25 15 53.8 304 -25 35 50.5 305 -25 45 55.0 306 -25 55 58.9 307 -25 65 59.0 308 -25 75 60.8 309 -25 85 62.6 310 -25 95 64.3 311 -25 105 63.3 312 -25 115 45.7 315 -25 145 58.7 316 -25 155 56.2 317 -25 165 58.9 318 -25 175 64.3 319 -25 185 66.3 320 -25 195 71.0 321 -25 205 71.3 322 -25 215 67.1 323 -25 225 63.3 324 -25 235 59.0 325 -25 245 54.3 326 -25 255 57.2 327 -25 265 65.4 328 -25 275 67.3 329 -25 285 77.2 332 -25 315 58.4 333 -25 325 57.9 334 -25 335 59.6 335 -25 345 58.5 336 -25 355 58.4 337 -35 5 70.6 338 -35 15 55.0 339 -35 25 55.3 340 -35 35 58.1 341 -35 45 62.3 342 -35 55 67.9 343 -35 65 69.8 344 -35 75 69.5 345 -35 85 71.2 346 -35 95 74.0 347 -35 105 73.6 348 -35 115 64.4 349 -35 125 70.6 350 -35 135 70.0 351 -35 145 64.6 352 -35 155 59.4 353 -35 165 65.9 354 -35 175 61.9 355 -35 185 65.5 356 -35 195 69.7 357 -35 205 72.3 358 -35 215 73.5 359 -35 225 75.8 360 -35 235 68.0 361 -35 245 74.0 362 -35 255 75.7 363 -35 265 71.3 364 -35 275 73.9 365 -35 285 65.7 367 -35 305 56.0 368 -35 315 63.5 369 -35 325 69.3 370 -35 335 70.5 371 -35 345 70.6 372 -35 355 70.8 373 -45 5 78.4 374 -45 15 78.7 375 -45 25 80.8 376 -45 35 80.8 377 -45 45 81.9 378 -45 55 81.0 379 -45 65 80.8 380 -45 75 81.3 381 -45 85 85.0 382 -45 95 81.6 383 -45 105 85.5 384 -45 115 84.4 385 -45 125 79.1 386 -45 135 80.4 387 -45 145 70.6 388 -45 155 72.1 389 -45 165 77.6 390 -45 175 64.2 391 -45 185 75.2 392 -45 195 80.1 393 -45 205 80.5 394 -45 215 80.3 395 -45 225 85.7 396 -45 235 85.2 397 -45 245 83.9 398 -45 255 78.6 399 -45 265 79.7 400 -45 275 83.0 401 -45 285 82.5 402 -45 295 62.0 403 -45 305 63.4 404 -45 315 73.8 405 -45 325 77.2 406 -45 335 78.4 407 -45 345 75.2 408 -45 355 78.1 409 -55 10 84.3 410 -55 30 85.3 411 -55 50 85.6 412 -55 70 86.4 413 -55 90 89.2 414 -55 110 86.4 416 -55 150 84.7 417 -55 170 85.8 419 -55 210 88.2 420 -55 230 84.2 421 -55 250 88.8 422 -55 270 81.7 423 -55 290 75.6 424 -55 310 80.7 425 -55 330 82.7 426 -55 350 82.1 427 -65 10 86.5 428 -65 30 90.5 429 -65 50 87.5 430 -65 70 88.9 431 -65 90 90.4 432 -65 110 90.1 433 -65 130 91.6 434 -65 150 86.1 435 -65 170 92.9 440 -65 270 89.2 441 -65 290 82.0 442 -65 310 90.1 443 -65 330 86.9 444 -65 350 86.5 450 -75 220 80.3