Cumulus Frequency of Occurrence (%) March, April, May (1954 - 1997) Night, Ship Observations Only Global Average: 32.2 Zonal Averages 17 zones Lat.N Average 85 2.0 75 4.9 65 13.2 55 12.0 45 13.6 35 23.7 25 38.4 15 48.9 5 45.7 -5 51.3 -15 48.1 -25 41.5 -35 29.3 -45 17.1 -55 14.0 -65 7.3 -75 4.6 Grid Box Averages 388 filled boxes Box # Lat.N Lon.E Average 1 85 60 4.7 2 85 180 0.4 3 85 300 0.5 4 75 20 12.0 5 75 60 5.5 6 75 100 4.6 7 75 140 2.1 8 75 180 0.7 9 75 220 0.8 11 75 300 10.7 12 75 340 7.0 13 65 10 13.2 14 65 30 11.1 15 65 50 9.4 20 65 150 11.6 21 65 170 8.2 22 65 190 6.2 23 65 210 11.2 27 65 290 24.6 29 65 330 13.2 30 65 350 13.9 31 55 10 12.8 32 55 30 10.3 37 55 130 11.5 38 55 150 8.9 39 55 170 9.3 40 55 190 9.7 41 55 210 11.7 42 55 230 14.4 45 55 290 25.5 46 55 310 14.1 47 55 330 13.0 48 55 350 13.8 49 45 5 18.9 50 45 15 18.1 51 45 25 12.8 52 45 35 13.1 53 45 45 11.9 54 45 55 9.8 62 45 135 12.0 63 45 145 12.0 64 45 155 8.7 65 45 165 7.4 66 45 175 9.1 67 45 185 10.9 68 45 195 11.1 69 45 205 11.5 70 45 215 12.7 71 45 225 16.0 72 45 235 18.5 77 45 285 8.9 78 45 295 10.5 79 45 305 10.9 80 45 315 15.9 81 45 325 19.6 82 45 335 18.7 83 45 345 19.4 84 45 355 20.9 85 35 5 21.7 86 35 15 21.1 87 35 25 22.6 88 35 35 29.4 89 35 45 19.1 90 35 55 11.7 96 35 115 8.2 97 35 125 12.3 98 35 135 23.6 99 35 145 22.3 100 35 155 18.3 101 35 165 18.3 102 35 175 18.0 103 35 185 18.6 104 35 195 18.8 105 35 205 19.1 106 35 215 20.5 107 35 225 21.9 108 35 235 21.9 109 35 245 19.1 112 35 275 25.6 113 35 285 26.6 114 35 295 30.0 115 35 305 32.4 116 35 315 36.4 117 35 325 32.7 118 35 335 28.9 119 35 345 30.0 120 35 355 23.3 124 25 35 8.1 125 25 45 9.8 126 25 55 10.0 127 25 65 24.8 128 25 75 26.2 129 25 85 34.0 130 25 95 34.0 131 25 105 9.3 132 25 115 24.7 133 25 125 28.0 134 25 135 34.4 135 25 145 43.5 136 25 155 38.7 137 25 165 38.2 138 25 175 39.5 139 25 185 41.6 140 25 195 47.3 141 25 205 47.1 142 25 215 34.9 143 25 225 24.9 144 25 235 23.1 145 25 245 22.8 146 25 255 26.8 147 25 265 32.0 148 25 275 45.3 149 25 285 45.0 150 25 295 51.8 151 25 305 54.0 152 25 315 50.9 153 25 325 47.0 154 25 335 43.7 155 25 345 29.6 160 15 35 13.4 161 15 45 27.7 162 15 55 49.6 163 15 65 50.0 164 15 75 50.3 165 15 85 51.1 166 15 95 51.1 167 15 105 33.5 168 15 115 56.6 169 15 125 51.9 170 15 135 59.4 171 15 145 58.6 172 15 155 59.7 173 15 165 61.8 174 15 175 55.4 175 15 185 51.9 176 15 195 53.9 177 15 205 52.2 178 15 215 38.8 179 15 225 30.8 180 15 235 27.1 181 15 245 37.7 182 15 255 40.7 183 15 265 38.8 184 15 275 49.8 185 15 285 52.5 186 15 295 59.3 187 15 305 62.5 188 15 315 56.7 189 15 325 47.8 190 15 335 40.1 191 15 345 11.1 193 5 5 41.3 197 5 45 66.5 198 5 55 65.1 199 5 65 66.3 200 5 75 51.4 201 5 85 49.2 202 5 95 44.0 203 5 105 55.5 204 5 115 53.7 205 5 125 47.4 206 5 135 47.6 207 5 145 42.5 208 5 155 39.0 209 5 165 46.6 210 5 175 47.2 211 5 185 47.5 212 5 195 47.6 213 5 205 43.1 214 5 215 37.9 215 5 225 38.1 216 5 235 43.5 217 5 245 45.5 218 5 255 47.8 219 5 265 42.0 220 5 275 33.8 221 5 285 29.3 223 5 305 51.2 224 5 315 41.1 225 5 325 41.3 226 5 335 43.4 227 5 345 30.3 228 5 355 39.7 229 -5 5 44.4 230 -5 15 33.0 232 -5 35 46.9 233 -5 45 60.3 234 -5 55 62.1 235 -5 65 58.3 236 -5 75 52.8 237 -5 85 49.5 238 -5 95 46.3 239 -5 105 46.2 240 -5 115 47.1 241 -5 125 48.4 242 -5 135 46.2 243 -5 145 40.4 244 -5 155 38.3 245 -5 165 45.7 246 -5 175 46.1 247 -5 185 55.6 248 -5 195 56.4 249 -5 205 63.8 250 -5 215 60.8 251 -5 225 59.9 252 -5 235 60.5 253 -5 245 54.6 254 -5 255 48.7 255 -5 265 40.8 256 -5 275 26.6 257 -5 285 22.7 260 -5 315 44.2 261 -5 325 50.1 262 -5 335 55.5 263 -5 345 59.9 264 -5 355 52.5 265 -15 5 21.6 266 -15 15 16.7 268 -15 35 56.6 269 -15 45 53.6 270 -15 55 53.4 271 -15 65 53.0 272 -15 75 53.6 273 -15 85 47.9 274 -15 95 44.9 275 -15 105 54.6 276 -15 115 42.1 277 -15 125 36.7 278 -15 135 47.5 279 -15 145 43.6 280 -15 155 47.3 281 -15 165 45.2 282 -15 175 42.6 283 -15 185 44.7 284 -15 195 48.2 285 -15 205 57.4 286 -15 215 62.5 287 -15 225 61.1 288 -15 235 62.5 289 -15 245 63.4 290 -15 255 52.9 291 -15 265 35.4 292 -15 275 28.2 293 -15 285 24.0 297 -15 325 57.3 298 -15 335 60.0 299 -15 345 55.4 300 -15 355 33.5 301 -25 5 23.5 302 -25 15 23.1 304 -25 35 51.6 305 -25 45 50.4 306 -25 55 50.3 307 -25 65 45.9 308 -25 75 44.8 309 -25 85 36.8 310 -25 95 36.9 311 -25 105 41.1 312 -25 115 32.6 315 -25 145 33.0 316 -25 155 47.3 317 -25 165 47.4 318 -25 175 39.9 319 -25 185 40.4 320 -25 195 41.7 321 -25 205 43.7 322 -25 215 44.0 323 -25 225 46.5 324 -25 235 52.5 325 -25 245 51.5 326 -25 255 50.2 327 -25 265 34.7 328 -25 275 26.8 329 -25 285 19.6 332 -25 315 38.6 333 -25 325 48.0 334 -25 335 46.0 335 -25 345 43.3 336 -25 355 34.6 337 -35 5 22.4 338 -35 15 25.1 339 -35 25 25.0 340 -35 35 40.0 341 -35 45 38.1 342 -35 55 32.1 343 -35 65 27.6 344 -35 75 25.4 345 -35 85 21.0 346 -35 95 17.6 347 -35 105 26.9 348 -35 115 29.0 349 -35 125 23.1 350 -35 135 22.3 351 -35 145 23.8 352 -35 155 34.9 353 -35 165 33.1 354 -35 175 34.1 355 -35 185 32.2 356 -35 195 32.4 357 -35 205 31.2 358 -35 215 26.9 359 -35 225 27.8 360 -35 235 33.2 361 -35 245 31.1 362 -35 255 30.0 363 -35 265 29.5 364 -35 275 27.7 365 -35 285 22.0 367 -35 305 27.3 368 -35 315 37.8 369 -35 325 35.7 370 -35 335 29.9 371 -35 345 29.3 372 -35 355 26.5 373 -45 5 10.0 374 -45 15 15.3 375 -45 25 11.8 376 -45 35 12.1 377 -45 45 15.2 378 -45 55 13.4 379 -45 65 17.4 380 -45 75 15.6 381 -45 85 9.8 382 -45 95 11.3 383 -45 105 15.8 384 -45 115 19.4 385 -45 125 14.4 386 -45 135 17.1 387 -45 145 22.8 388 -45 155 22.9 389 -45 165 18.5 390 -45 175 18.4 391 -45 185 16.4 392 -45 195 16.4 393 -45 205 18.5 394 -45 215 15.7 395 -45 225 19.1 396 -45 235 18.1 397 -45 245 14.9 398 -45 255 14.3 399 -45 265 22.6 400 -45 275 20.2 401 -45 285 22.3 402 -45 295 17.1 403 -45 305 19.3 404 -45 315 22.8 405 -45 325 20.1 406 -45 335 19.8 407 -45 345 22.1 408 -45 355 17.3 409 -55 10 11.5 410 -55 30 12.8 411 -55 50 15.6 412 -55 70 12.0 413 -55 90 11.3 414 -55 110 11.6 415 -55 130 17.7 416 -55 150 17.2 417 -55 170 15.9 418 -55 190 14.4 419 -55 210 9.9 420 -55 230 17.0 421 -55 250 11.6 422 -55 270 14.3 423 -55 290 14.1 424 -55 310 13.2 425 -55 330 12.6 426 -55 350 19.6 427 -65 10 7.7 428 -65 30 11.5 429 -65 50 7.1 430 -65 70 7.0 431 -65 90 6.0 432 -65 110 8.9 433 -65 130 9.7 434 -65 150 6.7 435 -65 170 4.9 436 -65 190 6.0 437 -65 210 8.9 438 -65 230 3.6 440 -65 270 7.5 441 -65 290 4.3 442 -65 310 7.3 443 -65 330 7.7 444 -65 350 9.3 449 -75 180 3.1 450 -75 220 4.9 453 -75 340 6.7