Cumulus Frequency of Occurrence (%) April (1954 - 1997) Night, Ship Observations Only Global Average: 32.4 Zonal Averages 16 zones Lat.N Average 85 3.3 75 4.8 65 12.6 55 12.6 45 14.1 35 23.5 25 37.7 15 49.7 5 45.7 -5 50.8 -15 48.6 -25 41.8 -35 29.1 -45 17.2 -55 13.1 -65 5.1 Grid Box Averages 330 filled boxes Box # Lat.N Lon.E Average 1 85 60 7.8 2 85 180 0.4 3 85 300 1.1 4 75 20 12.7 5 75 60 6.0 7 75 140 2.0 8 75 180 0.7 9 75 220 1.0 12 75 340 7.6 13 65 10 14.1 14 65 30 12.3 15 65 50 7.6 21 65 170 9.4 22 65 190 8.9 23 65 210 6.2 29 65 330 14.3 30 65 350 14.2 31 55 10 13.2 32 55 30 10.5 38 55 150 9.6 39 55 170 11.4 40 55 190 11.0 41 55 210 12.3 42 55 230 15.9 46 55 310 15.8 47 55 330 12.9 48 55 350 13.4 49 45 5 18.7 50 45 15 16.6 51 45 25 8.4 52 45 35 9.3 53 45 45 9.3 54 45 55 7.6 62 45 135 10.1 63 45 145 11.4 64 45 155 9.5 65 45 165 8.3 66 45 175 10.5 67 45 185 11.9 68 45 195 11.8 69 45 205 12.3 70 45 215 15.6 71 45 225 18.6 72 45 235 20.3 77 45 285 8.9 78 45 295 10.6 79 45 305 11.6 80 45 315 15.5 81 45 325 19.7 82 45 335 18.2 83 45 345 19.0 84 45 355 21.5 85 35 5 22.0 86 35 15 21.7 87 35 25 22.6 88 35 35 26.3 97 35 125 11.6 98 35 135 21.8 99 35 145 22.5 100 35 155 19.2 101 35 165 17.2 102 35 175 16.6 103 35 185 18.0 104 35 195 18.2 105 35 205 17.4 106 35 215 19.1 107 35 225 22.2 108 35 235 23.4 109 35 245 20.5 112 35 275 24.7 113 35 285 25.6 114 35 295 28.5 115 35 305 32.3 116 35 315 36.4 117 35 325 32.8 118 35 335 31.1 119 35 345 30.1 120 35 355 23.5 124 25 35 6.8 125 25 45 11.9 126 25 55 9.5 127 25 65 21.9 129 25 85 33.3 132 25 115 24.1 133 25 125 27.7 134 25 135 35.1 135 25 145 44.6 136 25 155 38.3 137 25 165 34.2 138 25 175 38.1 139 25 185 40.5 140 25 195 44.1 141 25 205 44.3 142 25 215 33.8 143 25 225 25.0 144 25 235 24.8 145 25 245 24.5 146 25 255 25.8 147 25 265 26.8 148 25 275 45.7 149 25 285 44.3 150 25 295 52.5 151 25 305 53.9 152 25 315 49.6 153 25 325 46.1 154 25 335 44.2 155 25 345 30.1 160 15 35 11.1 161 15 45 28.4 162 15 55 50.8 163 15 65 46.9 164 15 75 50.1 165 15 85 59.7 166 15 95 58.2 167 15 105 33.5 168 15 115 61.1 169 15 125 53.9 170 15 135 60.2 171 15 145 57.4 172 15 155 59.8 173 15 165 63.2 174 15 175 54.7 175 15 185 51.1 176 15 195 55.4 177 15 205 49.3 178 15 215 38.6 179 15 225 32.1 180 15 235 26.1 181 15 245 37.3 182 15 255 39.1 183 15 265 40.4 184 15 275 51.7 185 15 285 54.7 186 15 295 60.9 187 15 305 63.5 188 15 315 57.1 189 15 325 49.0 190 15 335 40.7 191 15 345 10.5 193 5 5 42.3 197 5 45 68.9 198 5 55 68.2 199 5 65 69.5 200 5 75 52.4 201 5 85 48.7 202 5 95 44.7 203 5 105 60.2 204 5 115 56.2 205 5 125 53.0 206 5 135 49.6 207 5 145 45.0 208 5 155 37.5 209 5 165 45.4 210 5 175 48.1 211 5 185 43.0 212 5 195 47.0 213 5 205 40.5 214 5 215 28.2 215 5 225 35.3 216 5 235 39.2 217 5 245 44.7 218 5 255 47.7 219 5 265 47.3 220 5 275 34.4 221 5 285 30.4 223 5 305 53.0 224 5 315 40.1 225 5 325 42.1 226 5 335 43.1 227 5 345 30.6 228 5 355 41.0 229 -5 5 44.7 230 -5 15 33.6 233 -5 45 60.1 234 -5 55 60.2 235 -5 65 55.0 236 -5 75 55.2 237 -5 85 50.8 238 -5 95 48.0 239 -5 105 44.3 240 -5 115 45.5 241 -5 125 53.1 242 -5 135 49.8 243 -5 145 43.0 244 -5 155 38.1 245 -5 165 40.8 246 -5 175 39.5 247 -5 185 56.5 248 -5 195 58.2 249 -5 205 68.1 250 -5 215 48.8 251 -5 225 59.8 252 -5 235 62.6 253 -5 245 53.0 254 -5 255 52.6 255 -5 265 40.7 256 -5 275 25.9 260 -5 315 42.1 261 -5 325 51.4 262 -5 335 51.7 263 -5 345 58.3 264 -5 355 50.7 265 -15 5 20.8 266 -15 15 18.4 268 -15 35 60.0 269 -15 45 53.4 270 -15 55 53.6 271 -15 65 51.1 272 -15 75 54.2 273 -15 85 46.1 274 -15 95 43.1 275 -15 105 57.9 276 -15 115 40.2 277 -15 125 39.3 278 -15 135 50.1 279 -15 145 49.3 280 -15 155 48.5 281 -15 165 51.2 282 -15 175 41.2 283 -15 185 45.1 284 -15 195 51.5 285 -15 205 56.7 286 -15 215 63.6 287 -15 225 64.0 288 -15 235 63.3 289 -15 245 64.3 290 -15 255 54.4 291 -15 265 33.5 292 -15 275 29.2 293 -15 285 21.9 297 -15 325 56.1 298 -15 335 59.5 299 -15 345 56.9 300 -15 355 31.0 301 -25 5 22.2 302 -25 15 21.4 304 -25 35 51.1 305 -25 45 50.3 306 -25 55 48.6 307 -25 65 44.8 308 -25 75 49.7 309 -25 85 37.5 310 -25 95 38.0 311 -25 105 45.5 312 -25 115 33.1 316 -25 155 49.3 317 -25 165 50.0 318 -25 175 39.7 319 -25 185 43.2 320 -25 195 40.1 321 -25 205 43.1 322 -25 215 43.5 323 -25 225 50.3 324 -25 235 50.9 325 -25 245 53.1 326 -25 255 44.2 327 -25 265 36.8 328 -25 275 25.6 329 -25 285 17.7 332 -25 315 40.3 333 -25 325 50.5 334 -25 335 42.8 335 -25 345 46.8 336 -25 355 33.4 337 -35 5 18.8 338 -35 15 22.4 339 -35 25 26.3 340 -35 35 39.0 341 -35 45 36.9 342 -35 55 34.1 343 -35 65 27.0 344 -35 75 25.5 345 -35 85 23.1 346 -35 95 17.3 347 -35 105 30.3 348 -35 115 29.3 349 -35 125 23.1 350 -35 135 21.5 351 -35 145 22.8 352 -35 155 34.3 353 -35 165 34.3 354 -35 175 34.5 355 -35 185 33.1 356 -35 195 36.1 357 -35 205 32.8 358 -35 215 27.8 359 -35 225 30.8 360 -35 235 37.8 363 -35 265 22.5 364 -35 275 28.7 365 -35 285 20.2 367 -35 305 27.1 368 -35 315 38.0 369 -35 325 32.5 370 -35 335 25.5 371 -35 345 28.6 372 -35 355 24.3 373 -45 5 7.6 377 -45 45 11.3 380 -45 75 9.2 381 -45 85 11.2 382 -45 95 12.3 386 -45 135 18.1 387 -45 145 22.8 388 -45 155 21.6 389 -45 165 18.9 390 -45 175 17.7 391 -45 185 16.6 392 -45 195 19.5 393 -45 205 23.9 394 -45 215 20.1 399 -45 265 19.9 400 -45 275 18.8 401 -45 285 19.6 402 -45 295 19.3 403 -45 305 18.3 404 -45 315 22.2 405 -45 325 14.5 409 -55 10 9.7 417 -55 170 12.2 422 -55 270 13.8 423 -55 290 16.9 424 -55 310 16.7 425 -55 330 10.2 427 -65 10 4.0 429 -65 50 3.9 430 -65 70 2.5 431 -65 90 3.4 433 -65 130 11.2 442 -65 310 6.3