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 2024-02-05.

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	32% 16% 4 7% 5% 3 4 4 4 4 17%	78103
	Night	34% 18% 4 7% 5% 3 3 3 3 4 17%	80709
Transparency	Day	73% 5% 9% 9% 3 1	77799
	Night	74% 4 9% 8% 4 1	80593
Seeing	Day	37% 15% 21% 18% 8% 1	15072
	Night	41% 12% 20% 18% 9% 1	22751

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	30% 22% 5% 7% 4 2 4 4 4 4 15%	2219
	11th to 20th	Day	32% 15% 4 5% 4 2 4 4 3 4 23%	2199
	21st to end	Day	52% 19% 3 4 4 2 2 2 2 2 7%	2566
February	1st to 10th	Day	35% 16% 4 6% 4 2 3 4 3 4 20%	1473
	11th to 20th	Day	24% 24% 4 6% 4 3 3 3 4 5% 21%	1510
	21st to end	Day	20% 21% 4 6% 4 3 3 4 3 5% 27%	1376
March	1st to 10th	Day	25% 20% 5% 6% 6% 3 4 3 4 4 21%	1800
	11th to 20th	Day	25% 23% 5% 9% 6% 4 4 5% 3 3 13%	1952
	21st to end	Day	23% 21% 4 8% 5% 2 5% 4 4 5% 19%	2217
April	1st to 10th	Day	25% 23% 6% 9% 6% 3 4 3 3 4 14%	2252
	11th to 20th	Day	25% 21% 4 8% 6% 3 3 3 4 5% 17%	2308
	21st to end	Day	28% 19% 5% 7% 6% 4 4 4 3 4 17%	2340
May	1st to 10th	Day	26% 17% 6% 8% 7% 4 4 3 4 4 17%	2669
	11th to 20th	Day	26% 13% 5% 7% 7% 3 5% 5% 5% 6% 19%	2656
	21st to end	Day	27% 11% 4 8% 8% 4 5% 5% 5% 6% 18%	2917
June	1st to 10th	Day	31% 12% 4 9% 6% 5% 5% 4 4 5% 15%	2700
	11th to 20th	Day	34% 13% 5% 8% 7% 2 4 4 4 6% 12%	2875
	21st to end	Day	34% 11% 4 8% 6% 3 4 5% 4 5% 16%	2880
July	1st to 10th	Day	28% 11% 4 7% 6% 3 4 5% 5% 5% 22%	2854
	11th to 20th	Day	31% 12% 4 7% 6% 4 4 4 4 5% 18%	2700
	21st to end	Day	33% 10% 4 6% 5% 3 5% 4 4 5% 22%	2938
August	1st to 10th	Day	23% 8% 3 7% 5% 3 5% 4 5% 6% 30%	2593
	11th to 20th	Day	29% 10% 3 6% 6% 3 3 4 4 6% 26%	2391
	21st to end	Day	38% 11% 4 8% 6% 4 4 4 3 4 14%	2574
September	1st to 10th	Day	37% 11% 3 7% 6% 2 4 3 4 5% 18%	2297
	11th to 20th	Day	31% 9% 3 6% 5% 3 5% 5% 4 5% 23%	1980
	21st to end	Day	46% 13% 4 7% 5% 2 3 2 3 3 11%	1980
October	1st to 10th	Day	36% 11% 3 6% 5% 2 3 4 5% 6% 19%	1872
	11th to 20th	Day	40% 17% 3 7% 6% 3 4 4 4 4 8%	1634
	21st to end	Day	39% 15% 4 5% 4 2 4 3 3 4 17%	1766
November	1st to 10th	Day	44% 17% 4 5% 5% 3 3 2 3 3 11%	1488
	11th to 20th	Day	38% 22% 3 9% 4 4 4 2 2 2 9%	1340
	21st to end	Day	35% 23% 5% 7% 5% 2 2 3 2 4 12%	1330
December	1st to 10th	Day	31% 19% 4 5% 4 2 3 3 3 4 22%	1330
	11th to 20th	Day	40% 18% 4 5% 4 2 4 3 3 3 14%	1685
	21st to end	Day	39% 25% 5% 7% 5% 3 3 2 2 1 8%	2442
January	1st to 10th	Night	35% 23% 5% 7% 4 3 3 3 3 3 11%	4726
	11th to 20th	Night	31% 15% 3 4 3 2 3 4 3 4 27%	4699
	21st to end	Night	54% 17% 3 4 3 2 2 2 2 2 8%	5090
February	1st to 10th	Night	35% 18% 5% 6% 3 2 3 2 3 4 20%	2581
	11th to 20th	Night	26% 23% 6% 7% 5% 2 3 3 3 5% 18%	2337
	21st to end	Night	17% 21% 5% 8% 5% 2 4 4 3 3 27%	1878
March	1st to 10th	Night	22% 20% 5% 7% 5% 3 4 4 4 5% 21%	2160
	11th to 20th	Night	24% 27% 6% 8% 7% 4 4 3 4 3 12%	2006
	21st to end	Night	24% 20% 6% 9% 7% 3 5% 4 4 4 16%	2138
April	1st to 10th	Night	23% 22% 6% 9% 6% 3 4 4 3 3 16%	1707
	11th to 20th	Night	24% 18% 4 8% 7% 3 5% 3 4 4 19%	1601
	21st to end	Night	27% 18% 5% 7% 4 3 4 4 4 4 21%	1620
May	1st to 10th	Night	28% 17% 5% 7% 5% 4 5% 4 5% 4 16%	1287
	11th to 20th	Night	25% 11% 4 8% 6% 3 7% 5% 5% 6% 19%	1239
	21st to end	Night	25% 14% 5% 7% 7% 3 5% 3 4 5% 21%	1358
June	1st to 10th	Night	34% 12% 4 7% 5% 3 3 4 3 4 21%	1260
	11th to 20th	Night	33% 17% 4 8% 7% 4 4 4 4 3 13%	1080
	21st to end	Night	33% 12% 4 8% 5% 3 5% 4 3 5% 18%	1080
July	1st to 10th	Night	31% 10% 5% 10% 6% 3 3 3 4 4 21%	1103
	11th to 20th	Night	32% 13% 5% 7% 6% 3 3 3 2 4 20%	1260
	21st to end	Night	34% 10% 3 6% 4 3 4 4 4 5% 24%	1379
August	1st to 10th	Night	25% 8% 4 7% 5% 3 4 4 5% 6% 28%	1345
	11th to 20th	Night	27% 9% 3 7% 7% 3 5% 4 4 6% 25%	1509
	21st to end	Night	37% 14% 3 8% 6% 4 3 4 4 3 15%	1782
September	1st to 10th	Night	38% 11% 3 6% 4 3 3 4 3 5% 21%	1662
	11th to 20th	Night	31% 11% 3 5% 4 2 3 3 4 5% 28%	1980
	21st to end	Night	50% 14% 4 6% 3 2 3 2 3 2 11%	1980
October	1st to 10th	Night	33% 12% 4 7% 5% 2 4 3 3 5% 22%	2088
	11th to 20th	Night	41% 14% 4 6% 6% 3 4 3 3 4 11%	2323
	21st to end	Night	40% 13% 3 6% 5% 2 3 3 4 4 17%	2589
November	1st to 10th	Night	43% 20% 4 6% 5% 2 3 3 2 3 10%	2590
	11th to 20th	Night	36% 23% 5% 7% 5% 3 3 3 3 3 10%	2838
	21st to end	Night	35% 24% 5% 7% 4 3 3 2 3 4 12%	2850
December	1st to 10th	Night	27% 21% 5% 6% 5% 2 3 3 3 4 19%	2850
	11th to 20th	Night	37% 20% 4 6% 5% 2 3 3 3 4 14%	3520
	21st to end	Night	40% 23% 5% 7% 5% 2 2 3 2 2 9%	5214

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% 3 10% 9% 3	2219
	11th to 20th	Day	69% 3 7% 5% 7% 9%	2220
	21st to end	Day	87% 2 4 4 2	2566
February	1st to 10th	Day	70% 5% 6% 8% 9% 2	1473
	11th to 20th	Day	68% 5% 9% 13% 5% 1	1518
	21st to end	Day	63% 5% 9% 15% 6% 3	1376
March	1st to 10th	Day	69% 5% 7% 10% 8% 1	1800
	11th to 20th	Day	78% 5% 6% 8% 2	1952
	21st to end	Day	71% 5% 10% 11% 3	2217
April	1st to 10th	Day	77% 6% 6% 9% 2	2252
	11th to 20th	Day	73% 5% 7% 13% 3	2308
	21st to end	Day	74% 5% 7% 10% 3	2340
May	1st to 10th	Day	73% 6% 9% 10% 1	2669
	11th to 20th	Day	67% 7% 11% 11% 3	2659
	21st to end	Day	70% 8% 10% 10% 2	2918
June	1st to 10th	Day	74% 6% 10% 7% 3	2700
	11th to 20th	Day	77% 8% 8% 7%	2875
	21st to end	Day	74% 7% 11% 6% 1	2880
July	1st to 10th	Day	65% 7% 13% 13% 1	2776
	11th to 20th	Day	71% 8% 13% 7% 1	2619
	21st to end	Day	68% 6% 12% 12% 2	2775
August	1st to 10th	Day	57% 8% 19% 14% 3	2575
	11th to 20th	Day	63% 8% 13% 13% 3	2391
	21st to end	Day	76% 7% 10% 5% 2	2574
September	1st to 10th	Day	71% 6% 13% 9% 1	2297
	11th to 20th	Day	65% 5% 14% 13% 3	1980
	21st to end	Day	81% 4 7% 6% 2	1980
October	1st to 10th	Day	68% 5% 13% 10% 4	1872
	11th to 20th	Day	82% 5% 8% 4 1	1634
	21st to end	Day	73% 4 8% 11% 3	1766
November	1st to 10th	Day	81% 3 6% 6% 2	1488
	11th to 20th	Day	82% 3 6% 4 4	1340
	21st to end	Day	78% 4 5% 7% 5% 1	1330
December	1st to 10th	Day	69% 3 12% 13% 3 1	1330
	11th to 20th	Day	79% 2 6% 7% 5% 1	1688
	21st to end	Day	85% 3 5% 4 4 1	2442
January	1st to 10th	Night	81% 3 7% 7% 2	4726
	11th to 20th	Night	64% 3 7% 6% 10% 10%	4740
	21st to end	Night	86% 2 4 5% 3	5090
February	1st to 10th	Night	71% 3 6% 8% 9% 3	2581
	11th to 20th	Night	71% 4 8% 11% 5% 1	2340
	21st to end	Night	63% 5% 9% 16% 6% 3	1878
March	1st to 10th	Night	66% 4 8% 11% 9% 1	2160
	11th to 20th	Night	78% 5% 7% 7% 3	2007
	21st to end	Night	73% 5% 8% 12% 2	2138
April	1st to 10th	Night	74% 6% 8% 9% 4	1707
	11th to 20th	Night	69% 5% 9% 13% 4	1601
	21st to end	Night	68% 5% 11% 12% 4	1620
May	1st to 10th	Night	71% 6% 12% 8% 2	1287
	11th to 20th	Night	66% 7% 13% 10% 3 1	1239
	21st to end	Night	68% 7% 13% 10% 2	1358
June	1st to 10th	Night	70% 6% 11% 10% 3	1260
	11th to 20th	Night	78% 5% 10% 6% 1	1080
	21st to end	Night	72% 7% 15% 4 2	1080
July	1st to 10th	Night	67% 8% 13% 12% 1	1072
	11th to 20th	Night	71% 7% 13% 8% 1	1218
	21st to end	Night	63% 9% 13% 12% 3	1302
August	1st to 10th	Night	58% 7% 21% 11% 3	1338
	11th to 20th	Night	61% 9% 15% 12% 3	1509
	21st to end	Night	74% 7% 12% 6% 2	1782
September	1st to 10th	Night	68% 7% 13% 10% 2	1662
	11th to 20th	Night	61% 5% 13% 18% 4	1980
	21st to end	Night	83% 3 5% 7% 3	1980
October	1st to 10th	Night	67% 5% 13% 11% 4	2088
	11th to 20th	Night	78% 6% 8% 5% 2	2323
	21st to end	Night	73% 4 9% 10% 4	2589
November	1st to 10th	Night	82% 3 6% 6% 3	2590
	11th to 20th	Night	82% 3 5% 5% 4	2838
	21st to end	Night	79% 3 5% 6% 5% 1	2850
December	1st to 10th	Night	70% 4 9% 13% 4	2850
	11th to 20th	Night	77% 2 8% 5% 6% 1	3516
	21st to end	Night	84% 2 5% 4 4 1	5214

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	38% 14% 25% 16% 6% 1	180
	11th to 20th	Day	52% 17% 15% 14% 2	180
	21st to end	Day	49% 9% 23% 16% 4	270
February	1st to 10th	Day	42% 19% 24% 12% 4	353
	11th to 20th	Day	41% 17% 22% 13% 6% 1	335
	21st to end	Day	38% 19% 28% 10% 6%	280
March	1st to 10th	Day	33% 21% 25% 12% 7% 1	340
	11th to 20th	Day	35% 18% 24% 16% 7%	408
	21st to end	Day	37% 19% 23% 13% 5% 1	462
April	1st to 10th	Day	40% 20% 23% 12% 5% 1	420
	11th to 20th	Day	29% 18% 23% 17% 10% 2	412
	21st to end	Day	38% 19% 22% 13% 6% 2	420
May	1st to 10th	Day	35% 15% 21% 22% 7% 1	598
	11th to 20th	Day	29% 12% 22% 24% 11% 2	625
	21st to end	Day	29% 16% 23% 23% 8% 1	680
June	1st to 10th	Day	38% 18% 20% 17% 7%	630
	11th to 20th	Day	36% 17% 20% 20% 6% 1	630
	21st to end	Day	33% 12% 20% 26% 8% 1	630
July	1st to 10th	Day	31% 10% 19% 23% 15% 1	621
	11th to 20th	Day	32% 15% 18% 23% 10% 1	618
	21st to end	Day	32% 16% 17% 21% 12% 2	684
August	1st to 10th	Day	24% 13% 18% 26% 17% 2	626
	11th to 20th	Day	32% 13% 22% 23% 10% 1	530
	21st to end	Day	42% 12% 23% 16% 6% 1	495
September	1st to 10th	Day	42% 12% 20% 17% 9%	450
	11th to 20th	Day	36% 12% 20% 21% 10% 1	450
	21st to end	Day	52% 16% 19% 9% 5%	450
October	1st to 10th	Day	40% 12% 18% 18% 9% 2	450
	11th to 20th	Day	48% 13% 19% 13% 6% 1	367
	21st to end	Day	46% 13% 19% 16% 6% 1	380
November	1st to 10th	Day	50% 16% 16% 13% 4 1	180
	11th to 20th	Day	50% 12% 18% 9% 10% 1	180
	21st to end	Day	53% 14% 11% 9% 11% 2	180
December	1st to 10th	Day	38% 14% 18% 18% 11% 1	180
	11th to 20th	Day	38% 14% 21% 19% 6% 2	180
	21st to end	Day	39% 14% 21% 17% 9% 1	198
January	1st to 10th	Night	45% 13% 22% 14% 6%	850
	11th to 20th	Night	53% 12% 20% 13% 3	850
	21st to end	Night	47% 12% 22% 14% 5% 1	935
February	1st to 10th	Night	45% 12% 25% 13% 5%	822
	11th to 20th	Night	40% 12% 24% 19% 5% 1	734
	21st to end	Night	33% 12% 30% 18% 7% 1	592
March	1st to 10th	Night	32% 11% 29% 20% 8%	720
	11th to 20th	Night	37% 16% 23% 20% 4	720
	21st to end	Night	33% 13% 22% 21% 11% 1	752
April	1st to 10th	Night	36% 12% 21% 21% 9% 1	540
	11th to 20th	Night	33% 12% 18% 26% 9% 1	533
	21st to end	Night	37% 10% 24% 22% 7% 1	540
May	1st to 10th	Night	35% 10% 20% 22% 13% 1	385
	11th to 20th	Night	29% 8% 24% 29% 10% 1	354
	21st to end	Night	32% 12% 19% 23% 14% 1	389
June	1st to 10th	Night	34% 10% 22% 18% 15% 1	360
	11th to 20th	Night	37% 14% 19% 18% 12% 1	360
	21st to end	Night	35% 11% 18% 26% 9% 1	360
July	1st to 10th	Night	31% 9% 15% 27% 16% 1	350
	11th to 20th	Night	36% 12% 13% 20% 18% 1	348
	21st to end	Night	32% 11% 12% 25% 18% 2	394
August	1st to 10th	Night	27% 10% 10% 22% 27% 4	450
	11th to 20th	Night	31% 10% 13% 22% 22% 2	534
	21st to end	Night	43% 10% 15% 21% 11%	594
September	1st to 10th	Night	44% 8% 15% 22% 11% 1	543
	11th to 20th	Night	35% 8% 15% 22% 17% 3	720
	21st to end	Night	52% 13% 15% 13% 7%	720
October	1st to 10th	Night	40% 9% 23% 18% 9% 2	720
	11th to 20th	Night	49% 12% 18% 14% 7%	720
	21st to end	Night	46% 10% 18% 19% 7%	792
November	1st to 10th	Night	55% 12% 19% 11% 3	740
	11th to 20th	Night	47% 14% 22% 13% 4 1	845
	21st to end	Night	51% 11% 20% 9% 7% 1	850
December	1st to 10th	Night	37% 12% 24% 20% 7%	850
	11th to 20th	Night	42% 15% 22% 18% 3	850
	21st to end	Night	42% 16% 22% 14% 6%	935

Page generated at 2024-02-02 02:20:28. Version ac07

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