Cumulonimbus Amount-When-Present (%) March, April, May (1954 - 1997) Night, Ship Observations Only Global Average: 59.0 Zonal Averages 15 zones Lat.N Average 75 83.9 65 72.7 55 69.6 45 65.7 35 62.0 25 54.3 15 49.9 5 52.2 -5 50.7 -15 51.7 -25 54.4 -35 58.7 -45 64.6 -55 69.3 -65 79.2 Grid Box Averages 295 filled boxes Box # Lat.N Lon.E Average 4 75 20 80.6 5 75 60 86.2 12 75 340 86.3 13 65 10 69.8 14 65 30 82.9 15 65 50 76.5 21 65 170 74.0 29 65 330 71.9 30 65 350 73.8 31 55 10 63.7 32 55 30 69.7 38 55 150 79.8 39 55 170 74.6 40 55 190 71.1 41 55 210 64.8 42 55 230 65.1 46 55 310 79.3 47 55 330 70.4 48 55 350 63.2 49 45 5 57.5 50 45 15 58.1 51 45 25 69.4 52 45 35 77.8 62 45 135 74.2 63 45 145 74.6 64 45 155 73.8 65 45 165 68.2 66 45 175 66.9 67 45 185 63.4 68 45 195 62.1 69 45 205 62.3 70 45 215 64.3 71 45 225 60.8 72 45 235 62.4 77 45 285 78.2 78 45 295 76.5 79 45 305 75.1 80 45 315 73.7 81 45 325 66.2 82 45 335 64.0 83 45 345 61.4 84 45 355 62.6 85 35 5 60.0 86 35 15 57.1 87 35 25 58.3 88 35 35 56.0 97 35 125 79.2 98 35 135 67.3 99 35 145 66.5 100 35 155 65.7 101 35 165 65.2 102 35 175 63.5 103 35 185 60.5 104 35 195 62.4 105 35 205 61.2 106 35 215 62.0 107 35 225 62.2 108 35 235 57.6 109 35 245 61.9 112 35 275 48.8 113 35 285 56.2 114 35 295 63.9 115 35 305 62.8 116 35 315 60.5 117 35 325 59.6 118 35 335 62.4 119 35 345 61.2 120 35 355 57.2 124 25 35 50.8 126 25 55 53.8 127 25 65 50.0 132 25 115 64.6 133 25 125 59.0 134 25 135 51.6 135 25 145 51.7 136 25 155 53.9 137 25 165 51.2 138 25 175 53.4 139 25 185 51.8 140 25 195 51.3 141 25 205 55.9 142 25 215 59.8 143 25 225 63.6 144 25 235 65.8 145 25 245 56.5 146 25 255 49.9 147 25 265 50.2 148 25 275 45.3 149 25 285 49.2 150 25 295 50.8 151 25 305 54.1 152 25 315 55.2 153 25 325 57.9 154 25 335 60.3 155 25 345 56.9 161 15 45 46.5 162 15 55 44.2 163 15 65 46.2 164 15 75 50.8 165 15 85 53.2 166 15 95 55.1 167 15 105 41.8 168 15 115 44.9 169 15 125 43.8 170 15 135 46.1 171 15 145 45.5 172 15 155 48.6 173 15 165 47.5 174 15 175 49.7 175 15 185 49.7 176 15 195 48.7 177 15 205 53.6 178 15 215 55.5 179 15 225 65.0 180 15 235 65.6 181 15 245 58.6 182 15 255 47.3 183 15 265 44.2 184 15 275 45.1 185 15 285 47.5 186 15 295 46.8 187 15 305 50.2 188 15 315 49.7 189 15 325 52.6 190 15 335 58.5 191 15 345 54.1 193 5 5 53.9 197 5 45 43.7 198 5 55 44.1 199 5 65 48.7 200 5 75 49.0 201 5 85 48.4 202 5 95 49.4 203 5 105 43.3 204 5 115 44.0 205 5 125 48.1 206 5 135 48.3 207 5 145 52.7 208 5 155 53.1 209 5 165 54.8 210 5 175 54.2 211 5 185 51.8 212 5 195 51.9 213 5 205 57.9 214 5 215 53.4 215 5 225 57.3 216 5 235 53.2 217 5 245 55.1 218 5 255 49.0 219 5 265 50.1 220 5 275 51.6 221 5 285 52.8 223 5 305 53.9 224 5 315 56.7 225 5 325 57.0 226 5 335 60.2 227 5 345 58.6 228 5 355 58.1 229 -5 5 56.8 230 -5 15 60.9 233 -5 45 47.2 234 -5 55 50.6 235 -5 65 49.7 236 -5 75 48.3 237 -5 85 48.5 238 -5 95 49.9 239 -5 105 49.9 240 -5 115 48.3 241 -5 125 46.8 242 -5 135 53.8 243 -5 145 53.2 244 -5 155 53.8 245 -5 165 54.5 246 -5 175 50.8 247 -5 185 47.9 248 -5 195 46.6 249 -5 205 47.2 250 -5 215 48.9 251 -5 225 50.0 252 -5 235 52.3 253 -5 245 52.0 254 -5 255 51.1 255 -5 265 52.7 256 -5 275 51.6 260 -5 315 50.3 261 -5 325 54.0 262 -5 335 54.7 263 -5 345 51.8 264 -5 355 52.1 265 -15 5 66.7 266 -15 15 65.7 268 -15 35 43.6 269 -15 45 47.8 270 -15 55 50.9 271 -15 65 54.0 272 -15 75 52.6 273 -15 85 54.2 274 -15 95 52.9 275 -15 105 50.5 276 -15 115 48.3 277 -15 125 44.1 278 -15 135 59.5 279 -15 145 59.0 280 -15 155 55.1 281 -15 165 52.6 282 -15 175 55.9 283 -15 185 50.4 284 -15 195 48.9 285 -15 205 47.3 286 -15 215 49.0 287 -15 225 45.0 288 -15 235 49.3 289 -15 245 47.3 290 -15 255 52.9 291 -15 265 58.6 292 -15 275 62.4 293 -15 285 55.3 297 -15 325 50.2 298 -15 335 48.6 299 -15 345 46.1 300 -15 355 61.5 301 -25 5 60.4 302 -25 15 58.6 304 -25 35 51.1 305 -25 45 54.0 306 -25 55 52.1 307 -25 65 54.7 308 -25 75 54.0 309 -25 85 55.7 310 -25 95 56.1 311 -25 105 60.5 312 -25 115 52.1 316 -25 155 55.4 317 -25 165 57.6 318 -25 175 51.9 319 -25 185 52.8 320 -25 195 57.4 321 -25 205 53.3 322 -25 215 52.3 323 -25 225 49.8 324 -25 235 49.3 325 -25 245 52.5 328 -25 275 60.9 329 -25 285 63.2 332 -25 315 54.4 333 -25 325 55.4 334 -25 335 52.5 335 -25 345 55.5 336 -25 355 56.1 337 -35 5 60.9 338 -35 15 56.9 339 -35 25 57.9 340 -35 35 56.7 341 -35 45 57.0 342 -35 55 56.6 343 -35 65 58.8 344 -35 75 59.3 345 -35 85 62.3 346 -35 95 63.1 347 -35 105 57.9 348 -35 115 59.7 349 -35 125 60.1 350 -35 135 61.8 351 -35 145 67.2 352 -35 155 58.2 353 -35 165 57.4 354 -35 175 53.5 355 -35 185 55.4 356 -35 195 55.7 357 -35 205 55.5 358 -35 215 61.6 359 -35 225 55.9 364 -35 275 74.1 367 -35 305 61.6 368 -35 315 60.5 369 -35 325 67.6 370 -35 335 58.0 371 -35 345 47.0 372 -35 355 61.1 387 -45 145 63.2 388 -45 155 60.6 389 -45 165 67.1 390 -45 175 57.0 391 -45 185 63.2 392 -45 195 64.9 400 -45 275 75.1 401 -45 285 69.0 402 -45 295 65.1 403 -45 305 64.0 417 -55 170 73.9 423 -55 290 65.2 424 -55 310 69.4 425 -55 330 70.0 430 -65 70 84.5 442 -65 310 74.3