Total Cloud Cover Average Cloud Amount (%) April (1954 - 1997) Night, Ship Observations Only Global Average: 66.3 Zonal Averages 16 zones Lat.N Average 85 55.5 75 64.5 65 76.3 55 79.7 45 77.5 35 69.6 25 59.2 15 52.4 5 60.8 -5 58.0 -15 57.9 -25 62.9 -35 67.6 -45 77.7 -55 81.3 -65 85.7 Grid Box Averages 338 filled boxes Box # Lat.N Lon.E Average 1 85 60 56.3 2 85 180 52.3 3 85 300 59.0 4 75 20 81.5 5 75 60 70.3 7 75 140 43.9 8 75 180 54.9 9 75 220 63.0 11 75 300 57.7 12 75 340 80.1 13 65 10 75.6 14 65 30 75.9 15 65 50 62.6 21 65 170 77.9 22 65 190 73.5 23 65 210 73.1 27 65 290 65.5 28 65 310 76.8 29 65 330 82.3 30 65 350 81.6 31 55 10 66.3 32 55 30 62.4 38 55 150 72.4 39 55 170 80.5 40 55 190 85.2 41 55 210 82.0 42 55 230 76.7 46 55 310 85.3 47 55 330 83.6 48 55 350 74.4 49 45 5 52.2 50 45 15 51.7 51 45 25 61.1 52 45 35 61.6 53 45 45 54.6 54 45 55 37.8 62 45 135 51.4 63 45 145 62.6 64 45 155 81.5 65 45 165 86.0 66 45 175 86.8 67 45 185 85.8 68 45 195 85.6 69 45 205 85.5 70 45 215 82.3 71 45 225 79.5 72 45 235 72.5 77 45 285 59.6 78 45 295 66.0 79 45 305 76.7 80 45 315 80.5 81 45 325 79.0 82 45 335 79.6 83 45 345 75.9 84 45 355 67.5 85 35 5 53.9 86 35 15 48.5 87 35 25 43.9 88 35 35 40.8 97 35 125 59.8 98 35 135 63.3 99 35 145 68.6 100 35 155 78.5 101 35 165 81.7 102 35 175 81.2 103 35 185 81.6 104 35 195 79.9 105 35 205 81.7 106 35 215 79.5 107 35 225 77.5 108 35 235 63.5 109 35 245 52.5 112 35 275 43.9 113 35 285 55.2 114 35 295 68.5 115 35 305 69.4 116 35 315 68.6 117 35 325 66.8 118 35 335 68.7 119 35 345 65.7 120 35 355 50.0 124 25 35 18.0 125 25 45 39.6 126 25 55 27.5 127 25 65 23.7 129 25 85 48.2 132 25 115 69.6 133 25 125 69.5 134 25 135 63.5 135 25 145 59.2 136 25 155 63.2 137 25 165 65.7 138 25 175 63.6 139 25 185 63.4 140 25 195 63.6 141 25 205 65.2 142 25 215 71.0 143 25 225 77.1 144 25 235 76.0 145 25 245 50.5 146 25 255 37.7 147 25 265 54.7 148 25 275 46.6 149 25 285 50.2 150 25 295 51.5 151 25 305 52.3 152 25 315 55.0 153 25 325 57.1 154 25 335 59.0 155 25 345 43.6 160 15 35 17.9 161 15 45 28.0 162 15 55 27.9 163 15 65 24.7 164 15 75 35.4 165 15 85 44.3 166 15 95 42.9 167 15 105 55.4 168 15 115 40.0 169 15 125 45.9 170 15 135 49.1 171 15 145 52.0 172 15 155 53.7 173 15 165 57.6 174 15 175 56.6 175 15 185 58.9 176 15 195 63.6 177 15 205 64.5 178 15 215 70.7 179 15 225 75.8 180 15 235 78.1 181 15 245 61.9 182 15 255 40.3 183 15 265 42.8 184 15 275 47.7 185 15 285 48.8 186 15 295 45.2 187 15 305 50.2 188 15 315 54.0 189 15 325 61.9 190 15 335 55.7 191 15 345 28.7 193 5 5 67.3 197 5 45 42.5 198 5 55 38.2 199 5 65 38.6 200 5 75 52.6 201 5 85 59.8 202 5 95 66.7 203 5 105 51.1 204 5 115 49.5 205 5 125 52.2 206 5 135 60.2 207 5 145 65.3 208 5 155 68.4 209 5 165 68.5 210 5 175 64.3 211 5 185 66.7 212 5 195 69.8 213 5 205 69.9 214 5 215 72.7 215 5 225 68.0 216 5 235 65.6 217 5 245 56.1 218 5 255 52.7 219 5 265 56.1 220 5 275 62.5 221 5 285 58.4 223 5 305 59.7 224 5 315 70.4 225 5 325 68.3 226 5 335 64.2 227 5 345 54.4 228 5 355 65.1 229 -5 5 66.1 230 -5 15 54.3 233 -5 45 49.9 234 -5 55 47.6 235 -5 65 52.6 236 -5 75 57.2 237 -5 85 59.7 238 -5 95 65.9 239 -5 105 65.2 240 -5 115 57.6 241 -5 125 55.8 242 -5 135 62.8 243 -5 145 69.7 244 -5 155 70.2 245 -5 165 68.8 246 -5 175 62.4 247 -5 185 60.0 248 -5 195 53.7 249 -5 205 50.9 250 -5 215 53.1 251 -5 225 49.2 252 -5 235 50.1 253 -5 245 56.4 254 -5 255 57.0 255 -5 265 60.7 256 -5 275 62.9 257 -5 285 51.6 260 -5 315 71.2 261 -5 325 61.3 262 -5 335 56.6 263 -5 345 50.6 264 -5 355 59.0 265 -15 5 77.3 266 -15 15 66.1 268 -15 35 43.6 269 -15 45 50.5 270 -15 55 55.3 271 -15 65 56.5 272 -15 75 55.3 273 -15 85 63.6 274 -15 95 65.0 275 -15 105 54.2 276 -15 115 34.0 277 -15 125 36.3 278 -15 135 56.1 279 -15 145 62.8 280 -15 155 65.4 281 -15 165 60.6 282 -15 175 67.3 283 -15 185 64.1 284 -15 195 57.7 285 -15 205 55.1 286 -15 215 50.9 287 -15 225 50.5 288 -15 235 48.4 289 -15 245 51.4 290 -15 255 56.9 291 -15 265 70.4 292 -15 275 77.1 293 -15 285 57.0 297 -15 325 55.4 298 -15 335 50.0 299 -15 345 48.9 300 -15 355 70.4 301 -25 5 74.8 302 -25 15 52.8 304 -25 35 48.7 305 -25 45 54.8 306 -25 55 58.6 307 -25 65 63.8 308 -25 75 61.9 309 -25 85 65.1 310 -25 95 67.3 311 -25 105 64.5 312 -25 115 41.7 316 -25 155 52.7 317 -25 165 58.8 318 -25 175 65.1 319 -25 185 67.6 320 -25 195 69.6 321 -25 205 70.4 322 -25 215 65.3 323 -25 225 59.4 324 -25 235 58.5 325 -25 245 57.5 326 -25 255 61.3 327 -25 265 71.3 328 -25 275 76.1 329 -25 285 75.8 332 -25 315 58.8 333 -25 325 55.3 334 -25 335 59.4 335 -25 345 57.4 336 -25 355 65.4 337 -35 5 75.5 338 -35 15 51.8 339 -35 25 53.3 340 -35 35 60.1 341 -35 45 63.8 342 -35 55 69.8 343 -35 65 69.7 344 -35 75 74.5 345 -35 85 75.5 346 -35 95 78.8 347 -35 105 71.9 348 -35 115 60.1 349 -35 125 69.1 350 -35 135 69.0 351 -35 145 61.5 352 -35 155 57.8 353 -35 165 65.8 354 -35 175 61.3 355 -35 185 68.8 356 -35 195 68.6 357 -35 205 73.3 358 -35 215 76.2 359 -35 225 73.0 360 -35 235 63.7 363 -35 265 71.7 364 -35 275 72.7 365 -35 285 58.0 367 -35 305 53.3 368 -35 315 61.8 369 -35 325 66.8 370 -35 335 70.7 371 -35 345 67.2 372 -35 355 71.9 373 -45 5 84.1 377 -45 45 81.5 378 -45 55 83.1 379 -45 65 82.0 380 -45 75 81.9 381 -45 85 86.2 382 -45 95 88.6 386 -45 135 77.1 387 -45 145 65.9 388 -45 155 69.8 389 -45 165 75.2 390 -45 175 62.3 391 -45 185 76.8 392 -45 195 76.1 393 -45 205 77.1 394 -45 215 81.6 399 -45 265 78.6 400 -45 275 83.7 401 -45 285 78.6 402 -45 295 59.2 403 -45 305 68.7 404 -45 315 75.8 405 -45 325 81.0 409 -55 10 82.1 413 -55 90 88.6 417 -55 170 82.5 422 -55 270 85.6 423 -55 290 71.6 424 -55 310 76.6 425 -55 330 80.7 427 -65 10 85.7 429 -65 50 83.2 430 -65 70 88.9 431 -65 90 87.3 433 -65 130 87.2 441 -65 290 81.7 442 -65 310 86.2