Cumulonimbus Amount-When-Present (%) December, January, February (1954 - 1997) Night, Ship Observations Only Global Average: 59.4 Zonal Averages 16 zones Lat.N Average 75 83.8 65 74.8 55 71.8 45 68.3 35 63.5 25 56.3 15 52.2 5 55.4 -5 52.9 -15 51.8 -25 52.3 -35 58.3 -45 61.5 -55 68.6 -65 74.1 -75 63.9 Grid Box Averages 318 filled boxes Box # Lat.N Lon.E Average 4 75 20 83.3 5 75 60 84.7 12 75 340 83.6 13 65 10 71.9 14 65 30 90.7 21 65 170 77.9 22 65 190 82.7 29 65 330 70.9 30 65 350 78.1 31 55 10 69.9 38 55 150 81.1 39 55 170 70.0 40 55 190 69.9 41 55 210 68.0 42 55 230 68.1 46 55 310 85.3 47 55 330 70.4 48 55 350 65.1 49 45 5 63.3 50 45 15 67.2 51 45 25 84.8 52 45 35 84.0 62 45 135 82.6 63 45 145 78.6 64 45 155 72.5 65 45 165 64.9 66 45 175 62.1 67 45 185 63.6 68 45 195 59.9 69 45 205 63.3 70 45 215 62.7 71 45 225 63.7 72 45 235 65.5 77 45 285 80.5 78 45 295 79.1 79 45 305 81.2 80 45 315 77.5 81 45 325 69.1 82 45 335 64.8 83 45 345 64.3 84 45 355 66.4 85 35 5 62.8 86 35 15 62.5 87 35 25 62.9 88 35 35 60.6 97 35 125 78.2 98 35 135 74.3 99 35 145 68.4 100 35 155 64.3 101 35 165 63.6 102 35 175 62.2 103 35 185 58.7 104 35 195 60.0 105 35 205 59.7 106 35 215 60.3 107 35 225 62.6 108 35 235 61.4 109 35 245 59.4 112 35 275 58.7 113 35 285 66.5 114 35 295 70.5 115 35 305 64.5 116 35 315 62.2 117 35 325 61.5 118 35 335 62.8 119 35 345 61.9 120 35 355 60.7 124 25 35 51.6 126 25 55 51.3 127 25 65 53.7 132 25 115 67.3 133 25 125 69.0 134 25 135 58.9 135 25 145 56.8 136 25 155 56.5 137 25 165 54.8 138 25 175 54.1 139 25 185 52.5 140 25 195 55.6 141 25 205 55.3 142 25 215 56.5 143 25 225 57.9 144 25 235 63.4 145 25 245 56.4 146 25 255 54.2 147 25 265 59.3 148 25 275 50.8 149 25 285 52.9 150 25 295 52.6 151 25 305 54.8 152 25 315 55.9 153 25 325 58.2 154 25 335 60.5 155 25 345 58.2 160 15 35 52.3 161 15 45 49.3 162 15 55 50.5 163 15 65 49.7 164 15 75 45.3 165 15 85 56.2 166 15 95 48.2 167 15 105 57.7 168 15 115 54.1 169 15 125 52.9 170 15 135 53.4 171 15 145 50.0 172 15 155 50.7 173 15 165 52.9 174 15 175 54.3 175 15 185 54.6 176 15 195 53.6 177 15 205 50.7 178 15 215 57.2 179 15 225 58.7 180 15 235 60.1 181 15 245 59.3 182 15 255 45.2 183 15 265 36.8 184 15 275 46.1 185 15 285 48.4 186 15 295 47.4 187 15 305 49.7 188 15 315 50.2 189 15 325 53.4 190 15 335 52.7 191 15 345 54.8 193 5 5 54.7 197 5 45 44.7 198 5 55 52.0 199 5 65 53.6 200 5 75 50.2 201 5 85 52.8 202 5 95 52.1 203 5 105 54.2 204 5 115 55.3 205 5 125 52.0 206 5 135 49.5 207 5 145 50.8 208 5 155 54.8 209 5 165 61.0 210 5 175 58.7 211 5 185 57.8 212 5 195 55.3 213 5 205 61.1 214 5 215 61.2 215 5 225 61.3 216 5 235 56.8 217 5 245 59.6 218 5 255 57.1 219 5 265 56.4 220 5 275 48.4 221 5 285 51.7 223 5 305 51.6 224 5 315 56.6 225 5 325 59.3 226 5 335 60.2 227 5 345 56.2 228 5 355 57.7 229 -5 5 61.3 230 -5 15 58.2 233 -5 45 46.2 234 -5 55 52.2 235 -5 65 52.4 236 -5 75 51.5 237 -5 85 52.6 238 -5 95 53.3 239 -5 105 54.1 240 -5 115 53.5 241 -5 125 51.3 242 -5 135 50.7 243 -5 145 55.0 244 -5 155 51.9 245 -5 165 58.2 246 -5 175 54.3 247 -5 185 51.0 248 -5 195 50.2 252 -5 235 49.5 253 -5 245 53.9 254 -5 255 53.9 255 -5 265 55.1 256 -5 275 54.9 260 -5 315 53.2 261 -5 325 49.4 262 -5 335 49.8 263 -5 345 52.1 264 -5 355 58.6 265 -15 5 66.4 266 -15 15 66.7 268 -15 35 47.3 269 -15 45 48.8 270 -15 55 51.2 271 -15 65 50.6 272 -15 75 52.5 273 -15 85 53.8 274 -15 95 53.9 275 -15 105 53.5 276 -15 115 50.1 277 -15 125 49.8 278 -15 135 56.0 279 -15 145 55.2 280 -15 155 51.6 281 -15 165 49.1 282 -15 175 53.5 283 -15 185 49.5 284 -15 195 50.7 285 -15 205 49.8 286 -15 215 50.3 287 -15 225 46.2 288 -15 235 50.7 289 -15 245 45.4 290 -15 255 56.0 291 -15 265 60.2 292 -15 275 67.2 293 -15 285 57.9 297 -15 325 50.5 298 -15 335 47.3 299 -15 345 51.6 300 -15 355 60.0 301 -25 5 63.4 302 -25 15 55.3 304 -25 35 54.1 305 -25 45 52.5 306 -25 55 52.7 307 -25 65 52.8 308 -25 75 50.7 309 -25 85 52.0 310 -25 95 57.9 311 -25 105 62.8 312 -25 115 52.0 316 -25 155 53.8 317 -25 165 51.8 318 -25 175 52.6 319 -25 185 50.4 320 -25 195 51.7 321 -25 205 53.3 322 -25 215 53.2 323 -25 225 48.8 324 -25 235 44.8 325 -25 245 46.8 326 -25 255 52.3 328 -25 275 67.0 329 -25 285 59.7 332 -25 315 56.1 333 -25 325 51.8 334 -25 335 47.4 335 -25 345 52.4 336 -25 355 54.5 337 -35 5 57.6 338 -35 15 52.6 339 -35 25 57.1 340 -35 35 65.5 341 -35 45 51.2 342 -35 55 54.7 343 -35 65 65.4 344 -35 75 58.2 345 -35 85 55.2 346 -35 95 63.3 347 -35 105 59.0 348 -35 115 58.7 349 -35 125 63.6 350 -35 135 61.8 351 -35 145 61.6 352 -35 155 58.4 353 -35 165 54.2 354 -35 175 49.5 355 -35 185 54.8 356 -35 195 58.3 357 -35 205 53.6 358 -35 215 56.6 363 -35 265 74.6 364 -35 275 68.5 365 -35 285 67.9 367 -35 305 56.7 368 -35 315 57.2 369 -35 325 59.5 370 -35 335 55.8 371 -35 345 58.8 372 -35 355 58.1 380 -45 75 66.9 383 -45 105 62.9 387 -45 145 60.0 388 -45 155 61.1 389 -45 165 60.4 390 -45 175 56.9 391 -45 185 59.8 392 -45 195 57.9 400 -45 275 68.7 401 -45 285 65.8 402 -45 295 57.1 403 -45 305 61.5 409 -55 10 75.6 410 -55 30 71.2 411 -55 50 68.3 412 -55 70 67.8 413 -55 90 62.9 415 -55 130 71.1 416 -55 150 65.7 417 -55 170 69.2 422 -55 270 64.2 423 -55 290 62.8 424 -55 310 69.5 425 -55 330 77.5 426 -55 350 78.0 427 -65 10 75.3 428 -65 30 68.2 429 -65 50 68.4 430 -65 70 76.8 431 -65 90 77.0 432 -65 110 79.7 434 -65 150 72.5 435 -65 170 70.3 436 -65 190 76.1 437 -65 210 65.2 441 -65 290 76.4 442 -65 310 78.4 444 -65 350 75.0 449 -75 180 68.0 453 -75 340 55.7