Kitimat
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kitimat clear sky chart from 2005-11-06 to 2025-02-06.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	27% 16% 4 9% 5% 4 4 3 4 5% 19%	112658
	Night	29% 20% 5% 9% 4 4 3 3 3 4 18%	114242
Transparency	Day	68% 7% 10% 11% 4	112396
	Night	71% 6% 9% 10% 4 1	114150
Seeing	Day	36% 16% 21% 18% 8% 1	16404
	Night	40% 12% 21% 18% 9% 1	24054

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	27% 25% 5% 8% 3 3 3 3 4 4 14%	3179
	11th to 20th	Day	25% 19% 5% 8% 4 4 4 3 4 4 22%	3159
	21st to end	Day	39% 19% 4 7% 4 3 2 2 2 3 16%	3678
February	1st to 10th	Day	33% 16% 3 7% 4 3 2 3 3 4 21%	1561
	11th to 20th	Day	23% 23% 4 6% 3 4 3 2 5% 5% 23%	1596
	21st to end	Day	19% 23% 3 6% 4 4 3 4 3 5% 26%	1460
March	1st to 10th	Day	20% 21% 4 8% 5% 4 4 3 4 5% 23%	3126
	11th to 20th	Day	24% 22% 4 8% 5% 4 5% 4 5% 4 15%	3448
	21st to end	Day	17% 18% 3 8% 4 4 4 3 4 5% 31%	3902
April	1st to 10th	Day	24% 25% 5% 10% 5% 4 3 3 3 4 14%	2378
	11th to 20th	Day	23% 23% 4 9% 5% 4 4 2 4 5% 18%	2438
	21st to end	Day	27% 20% 4 8% 6% 4 3 3 3 4 18%	2470
May	1st to 10th	Day	22% 15% 4 9% 6% 4 5% 3 5% 7% 19%	4696
	11th to 20th	Day	32% 14% 4 8% 6% 5% 4 4 4 5% 14%	4696
	21st to end	Day	30% 16% 4 10% 6% 5% 4 3 4 4 14%	5161
June	1st to 10th	Day	31% 13% 4 9% 5% 5% 5% 3 5% 5% 15%	2850
	11th to 20th	Day	33% 14% 4 9% 6% 3 4 3 5% 6% 13%	3035
	21st to end	Day	33% 13% 3 9% 6% 4 4 4 4 5% 16%	3040
July	1st to 10th	Day	16% 9% 3 6% 5% 4 5% 4 6% 6% 37%	5006
	11th to 20th	Day	18% 10% 4 9% 6% 6% 6% 5% 7% 8% 23%	4740
	21st to end	Day	27% 11% 4 10% 6% 5% 6% 4 4 5% 19%	5138
August	1st to 10th	Day	14% 6% 2 6% 3 3 3 3 4 6% 50%	4548
	11th to 20th	Day	23% 13% 4 9% 5% 4 4 3 4 5% 28%	4185
	21st to end	Day	29% 13% 4 9% 4 5% 4 3 5% 6% 18%	4521
September	1st to 10th	Day	35% 11% 3 8% 4 4 3 2 5% 6% 18%	2423
	11th to 20th	Day	30% 10% 3 8% 4 5% 5% 4 4 5% 22%	2090
	21st to end	Day	46% 14% 4 9% 5% 2 3 2 3 3 11%	2090
October	1st to 10th	Day	34% 17% 7% 12% 5% 3 3 2 4 3 11%	3304
	11th to 20th	Day	37% 16% 4 11% 6% 5% 4 4 4 3 6%	2857
	21st to end	Day	26% 16% 6% 11% 6% 4 3 2 3 4 19%	3072
November	1st to 10th	Day	43% 19% 3 6% 5% 3 3 2 3 3 11%	1568
	11th to 20th	Day	35% 24% 3 9% 4 5% 4 2 3 2 9%	1410
	21st to end	Day	34% 23% 4 8% 4 3 2 2 3 4 13%	1400
December	1st to 10th	Day	30% 24% 6% 7% 4 2 3 2 3 3 15%	2290
	11th to 20th	Day	30% 21% 6% 10% 5% 4 4 2 4 3 13%	2645
	21st to end	Day	29% 26% 6% 13% 6% 4 3 2 2 2 6%	3498
January	1st to 10th	Night	29% 25% 6% 9% 4 3 3 2 3 3 12%	6766
	11th to 20th	Night	24% 18% 4 8% 4 3 3 3 4 5% 23%	6739
	21st to end	Night	41% 20% 4 6% 3 3 2 2 2 3 14%	7282
February	1st to 10th	Night	33% 19% 4 6% 3 3 2 2 3 3 22%	2730
	11th to 20th	Night	25% 24% 5% 8% 4 3 3 2 3 5% 20%	2471
	21st to end	Night	17% 23% 5% 8% 5% 3 4 3 4 3 26%	1992
March	1st to 10th	Night	19% 20% 4 6% 5% 4 3 3 5% 6% 25%	3738
	11th to 20th	Night	25% 26% 5% 9% 5% 5% 4 3 3 3 13%	3529
	21st to end	Night	16% 17% 4 8% 5% 4 4 3 4 5% 31%	3747
April	1st to 10th	Night	23% 24% 5% 10% 6% 4 4 3 3 3 16%	1801
	11th to 20th	Night	22% 20% 4 9% 6% 4 3 3 4 4 21%	1691
	21st to end	Night	26% 21% 3 8% 4 3 4 3 4 4 20%	1710
May	1st to 10th	Night	22% 22% 4 8% 4 5% 4 4 4 5% 18%	2261
	11th to 20th	Night	36% 14% 4 9% 5% 5% 4 3 4 4 11%	2199
	21st to end	Night	29% 19% 4 8% 5% 4 4 3 3 3 18%	2414
June	1st to 10th	Night	33% 13% 4 8% 5% 4 3 3 3 3 20%	1330
	11th to 20th	Night	32% 17% 3 9% 6% 5% 4 4 4 4 13%	1140
	21st to end	Night	33% 13% 4 9% 5% 5% 4 3 3 4 18%	1140
July	1st to 10th	Night	21% 9% 3 6% 3 2 2 2 3 5% 42%	1951
	11th to 20th	Night	19% 13% 4 9% 5% 5% 4 4 5% 8% 25%	2220
	21st to end	Night	27% 13% 4 9% 5% 4 4 4 4 5% 21%	2414
August	1st to 10th	Night	14% 5% 2 5% 3 3 3 2 4 5% 52%	2387
	11th to 20th	Night	24% 11% 4 11% 6% 5% 4 3 4 5% 24%	2653
	21st to end	Night	28% 19% 5% 10% 5% 4 4 3 4 3 16%	3146
September	1st to 10th	Night	36% 12% 3 7% 4 4 3 3 3 5% 21%	1756
	11th to 20th	Night	31% 12% 3 6% 4 3 3 2 4 5% 27%	2090
	21st to end	Night	49% 15% 3 7% 3 3 3 1 2 2 11%	2090
October	1st to 10th	Night	38% 18% 6% 10% 4 3 2 2 2 3 13%	3676
	11th to 20th	Night	38% 19% 6% 11% 5% 3 3 2 2 3 7%	4068
	21st to end	Night	27% 18% 5% 10% 5% 4 3 2 3 3 19%	4485
November	1st to 10th	Night	42% 21% 4 6% 4 3 2 2 2 3 11%	2730
	11th to 20th	Night	33% 26% 5% 8% 4 3 3 2 3 3 9%	2988
	21st to end	Night	33% 25% 4 8% 4 4 2 2 3 3 12%	3000
December	1st to 10th	Night	31% 26% 6% 8% 4 3 3 2 2 3 12%	4890
	11th to 20th	Night	29% 24% 5% 9% 4 3 2 2 3 3 14%	5560
	21st to end	Night	29% 25% 6% 12% 6% 5% 3 2 2 3 7%	7458

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	75% 4 8% 11% 2	3179
	11th to 20th	Day	67% 5% 8% 9% 5% 6%	3180
	21st to end	Day	75% 5% 8% 9% 2	3678
February	1st to 10th	Day	69% 5% 6% 9% 9% 3	1561
	11th to 20th	Day	66% 5% 9% 13% 5% 2	1604
	21st to end	Day	63% 5% 9% 15% 6% 3	1460
March	1st to 10th	Day	65% 4 5% 15% 9% 1	3126
	11th to 20th	Day	73% 6% 8% 12% 2	3448
	21st to end	Day	59% 5% 9% 19% 8%	3902
April	1st to 10th	Day	77% 6% 6% 8% 3	2378
	11th to 20th	Day	71% 5% 6% 13% 4 1	2438
	21st to end	Day	74% 5% 7% 10% 3	2470
May	1st to 10th	Day	65% 9% 10% 13% 3	4696
	11th to 20th	Day	74% 8% 9% 7% 2	4699
	21st to end	Day	75% 8% 6% 9% 2	5162
June	1st to 10th	Day	75% 6% 10% 7% 3	2850
	11th to 20th	Day	75% 8% 9% 8%	3035
	21st to end	Day	74% 7% 11% 6% 1	3040
July	1st to 10th	Day	47% 7% 14% 24% 9%	4928
	11th to 20th	Day	55% 13% 25% 6% 1	4659
	21st to end	Day	64% 10% 13% 11% 3	4976
August	1st to 10th	Day	35% 7% 14% 28% 15% 1	4530
	11th to 20th	Day	59% 8% 11% 16% 6%	4227
	21st to end	Day	66% 9% 16% 8% 1	4520
September	1st to 10th	Day	70% 6% 13% 10% 1	2423
	11th to 20th	Day	65% 5% 14% 13% 3	2090
	21st to end	Day	81% 4 7% 6% 2	2090
October	1st to 10th	Day	76% 7% 8% 6% 2	3304
	11th to 20th	Day	79% 10% 6% 3 2	2857
	21st to end	Day	67% 8% 9% 10% 6%	3072
November	1st to 10th	Day	81% 4 6% 6% 3	1568
	11th to 20th	Day	82% 4 6% 4 4	1410
	21st to end	Day	77% 4 5% 9% 5% 1	1400
December	1st to 10th	Day	74% 6% 10% 8% 2	2290
	11th to 20th	Day	77% 4 6% 10% 3 1	2648
	21st to end	Day	85% 4 5% 3 2	3498
January	1st to 10th	Night	78% 4 8% 9% 2	6766
	11th to 20th	Night	62% 6% 8% 9% 7% 7%	6780
	21st to end	Night	77% 5% 9% 6% 3	7282
February	1st to 10th	Night	69% 3 6% 8% 10% 4	2730
	11th to 20th	Night	69% 4 8% 12% 6% 1	2474
	21st to end	Night	63% 5% 10% 15% 5% 2	1992
March	1st to 10th	Night	59% 4 7% 16% 12% 1	3738
	11th to 20th	Night	78% 4 7% 8% 2	3530
	21st to end	Night	57% 5% 8% 22% 8%	3747
April	1st to 10th	Night	73% 6% 8% 10% 4	1801
	11th to 20th	Night	68% 5% 8% 13% 5% 1	1691
	21st to end	Night	69% 5% 10% 12% 4	1710
May	1st to 10th	Night	67% 7% 13% 12% 2	2261
	11th to 20th	Night	77% 6% 9% 6% 2	2199
	21st to end	Night	73% 6% 9% 8% 4	2414
June	1st to 10th	Night	70% 6% 10% 11% 3	1330
	11th to 20th	Night	76% 5% 11% 6% 1	1140
	21st to end	Night	72% 7% 15% 4 2	1140
July	1st to 10th	Night	46% 5% 14% 23% 11%	1920
	11th to 20th	Night	56% 12% 24% 6% 1	2178
	21st to end	Night	61% 10% 11% 15% 2	2337
August	1st to 10th	Night	34% 7% 15% 33% 11%	2380
	11th to 20th	Night	59% 10% 15% 14% 3	2677
	21st to end	Night	73% 7% 13% 6% 1	3146
September	1st to 10th	Night	66% 7% 14% 10% 2	1756
	11th to 20th	Night	62% 5% 13% 17% 3	2090
	21st to end	Night	82% 4 5% 6% 3	2090
October	1st to 10th	Night	77% 6% 8% 7% 2	3676
	11th to 20th	Night	81% 7% 6% 4 1	4068
	21st to end	Night	67% 8% 9% 11% 5%	4485
November	1st to 10th	Night	81% 3 6% 6% 3	2730
	11th to 20th	Night	82% 4 5% 5% 4	2988
	21st to end	Night	79% 3 6% 6% 5% 1	3000
December	1st to 10th	Night	78% 4 7% 8% 2	4890
	11th to 20th	Night	77% 4 7% 8% 4 1	5556
	21st to end	Night	83% 5% 6% 4 2	7458

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	37% 18% 24% 16% 5% 1	200
	11th to 20th	Day	51% 17% 16% 14% 3	200
	21st to end	Day	48% 9% 22% 15% 5%	296
February	1st to 10th	Day	40% 19% 25% 13% 4	386
	11th to 20th	Day	38% 17% 25% 13% 7% 1	365
	21st to end	Day	37% 20% 26% 10% 6% 1	307
March	1st to 10th	Day	32% 20% 27% 12% 7% 1	370
	11th to 20th	Day	33% 18% 25% 15% 7%	447
	21st to end	Day	35% 19% 24% 14% 6% 1	506
April	1st to 10th	Day	40% 20% 22% 12% 5% 1	460
	11th to 20th	Day	29% 17% 24% 19% 10% 2	452
	21st to end	Day	36% 20% 22% 12% 7% 2	460
May	1st to 10th	Day	33% 15% 22% 21% 7% 1	648
	11th to 20th	Day	30% 13% 22% 23% 10% 2	675
	21st to end	Day	30% 18% 22% 22% 7% 1	735
June	1st to 10th	Day	38% 18% 20% 17% 7%	680
	11th to 20th	Day	34% 17% 20% 20% 7% 1	680
	21st to end	Day	32% 14% 20% 25% 8% 1	680
July	1st to 10th	Day	29% 11% 20% 23% 15% 2	671
	11th to 20th	Day	30% 15% 20% 23% 10% 2	668
	21st to end	Day	33% 17% 17% 19% 11% 2	739
August	1st to 10th	Day	22% 12% 17% 28% 18% 3	676
	11th to 20th	Day	31% 14% 22% 23% 9% 1	575
	21st to end	Day	41% 13% 23% 16% 6% 1	539
September	1st to 10th	Day	40% 13% 20% 18% 9%	490
	11th to 20th	Day	36% 13% 20% 20% 10% 1	490
	21st to end	Day	52% 17% 19% 8% 4	490
October	1st to 10th	Day	41% 14% 18% 18% 8% 1	490
	11th to 20th	Day	48% 14% 20% 12% 6% 1	397
	21st to end	Day	44% 14% 20% 17% 6%	412
November	1st to 10th	Day	49% 18% 16% 13% 4 1	200
	11th to 20th	Day	47% 13% 20% 11% 10% 1	200
	21st to end	Day	52% 16% 11% 10% 11% 2	200
December	1st to 10th	Day	37% 16% 18% 19% 11% 1	200
	11th to 20th	Day	38% 15% 21% 19% 7% 2	200
	21st to end	Day	37% 15% 20% 17% 10%	220
January	1st to 10th	Night	44% 14% 23% 14% 5%	900
	11th to 20th	Night	51% 12% 20% 14% 3	900
	21st to end	Night	45% 12% 22% 14% 5% 1	990
February	1st to 10th	Night	44% 12% 25% 13% 5%	875
	11th to 20th	Night	38% 12% 26% 19% 5% 1	778
	21st to end	Night	32% 13% 29% 18% 7% 1	628
March	1st to 10th	Night	31% 11% 29% 21% 7%	760
	11th to 20th	Night	36% 16% 24% 20% 4	760
	21st to end	Night	31% 13% 22% 22% 11% 1	793
April	1st to 10th	Night	35% 13% 22% 21% 9% 1	570
	11th to 20th	Night	32% 13% 18% 27% 9% 1	563
	21st to end	Night	36% 10% 25% 22% 7% 1	570
May	1st to 10th	Night	34% 11% 20% 21% 13% 1	406
	11th to 20th	Night	30% 9% 23% 28% 10% 1	374
	21st to end	Night	33% 12% 19% 22% 13%	411
June	1st to 10th	Night	34% 11% 22% 18% 14% 1	380
	11th to 20th	Night	36% 14% 19% 18% 11% 1	380
	21st to end	Night	34% 12% 17% 26% 9% 1	380
July	1st to 10th	Night	31% 9% 17% 27% 15% 1	370
	11th to 20th	Night	35% 12% 14% 20% 18% 1	368
	21st to end	Night	32% 12% 13% 24% 18% 1	416
August	1st to 10th	Night	25% 10% 10% 24% 27% 4	476
	11th to 20th	Night	31% 10% 13% 23% 21% 2	564
	21st to end	Night	41% 11% 16% 20% 11%	627
September	1st to 10th	Night	42% 9% 15% 22% 10% 1	574
	11th to 20th	Night	36% 9% 15% 21% 16% 2	760
	21st to end	Night	51% 14% 15% 13% 7%	760
October	1st to 10th	Night	41% 9% 22% 17% 9% 1	760
	11th to 20th	Night	49% 12% 18% 14% 7%	760
	21st to end	Night	44% 11% 19% 20% 7%	836
November	1st to 10th	Night	54% 13% 19% 11% 3	780
	11th to 20th	Night	46% 15% 21% 13% 4 1	895
	21st to end	Night	50% 12% 20% 10% 7% 1	900
December	1st to 10th	Night	38% 12% 23% 19% 7%	900
	11th to 20th	Night	41% 15% 21% 19% 3	900
	21st to end	Night	40% 16% 22% 14% 7%	990

Page generated at 2025-02-03 00:05:54. Version ac07

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