Kamloops
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kamloops clear sky chart from 2005-11-06 to 2025-09-04.

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	6% 8% 3 8% 6% 5% 6% 5% 7% 8% 38%	129804
	Night	6% 10% 4 9% 6% 6% 6% 5% 7% 8% 34%	127599
Transparency	Day	40% 11% 18% 21% 9% 2	129517
	Night	44% 12% 18% 18% 8% 1	127463
Seeing	Day	13% 16% 28% 26% 14% 4	16769
	Night	13% 12% 27% 31% 16% 2	24986

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	6% 16% 6% 14% 7% 7% 6% 5% 7% 7% 17%	3179
	11th to 20th	Day	6% 11% 3 8% 7% 5% 6% 5% 7% 9% 33%	3360
	21st to end	Day	6% 14% 6% 11% 6% 6% 5% 4 6% 8% 26%	4004
February	1st to 10th	Day	7% 14% 5% 12% 7% 6% 6% 5% 7% 6% 25%	1650
	11th to 20th	Day	5% 13% 4 10% 6% 7% 7% 5% 7% 7% 29%	1755
	21st to end	Day	4 12% 5% 12% 7% 8% 6% 5% 8% 8% 25%	1585
March	1st to 10th	Day	2 7% 4 9% 6% 7% 8% 7% 8% 11% 31%	4518
	11th to 20th	Day	2 7% 3 10% 7% 7% 7% 6% 8% 9% 34%	4839
	21st to end	Day	7% 11% 4 10% 7% 7% 7% 5% 7% 7% 27%	5854
April	1st to 10th	Day	5% 13% 5% 10% 6% 7% 7% 7% 7% 9% 24%	2400
	11th to 20th	Day	6% 11% 4 10% 8% 6% 6% 5% 6% 9% 29%	2378
	21st to end	Day	7% 10% 4 9% 7% 7% 6% 5% 8% 8% 31%	2800
May	1st to 10th	Day	7% 8% 3 6% 5% 5% 5% 4 5% 7% 46%	6320
	11th to 20th	Day	7% 9% 3 8% 6% 6% 7% 6% 9% 11% 27%	6277
	21st to end	Day	10% 10% 3 9% 5% 5% 5% 4 7% 8% 33%	6985
June	1st to 10th	Day	13% 8% 3 7% 5% 6% 6% 5% 7% 8% 33%	3178
	11th to 20th	Day	13% 9% 3 8% 8% 6% 7% 5% 7% 7% 26%	3200
	21st to end	Day	7% 5% 3 8% 7% 6% 5% 5% 6% 8% 40%	3200
July	1st to 10th	Day	5% 3 1 4 3 3 4 4 5% 7% 59%	6928
	11th to 20th	Day	4 3 1 3 3 3 4 3 6% 7% 62%	6702
	21st to end	Day	3 3 1 4 3 3 4 4 7% 10% 58%	6874
August	1st to 10th	Day	2 2 1 4 3 4 4 4 7% 9% 59%	4541
	11th to 20th	Day	3 3 1 5% 4 4 6% 6% 7% 11% 49%	4421
	21st to end	Day	8% 4 2 5% 4 4 5% 4 7% 9% 50%	4440
September	1st to 10th	Day	6% 4 1 6% 5% 4 5% 3 5% 7% 53%	2317
	11th to 20th	Day	9% 7% 3 6% 6% 5% 6% 3 5% 8% 43%	2280
	21st to end	Day	10% 8% 2 7% 5% 6% 5% 4 8% 8% 37%	2039
October	1st to 10th	Day	7% 6% 3 8% 5% 6% 5% 4 6% 9% 43%	3180
	11th to 20th	Day	10% 11% 4 8% 5% 4 5% 4 5% 7% 37%	3082
	21st to end	Day	7% 10% 4 8% 6% 5% 5% 5% 7% 10% 34%	3101
November	1st to 10th	Day	10% 13% 3 11% 8% 7% 7% 4 5% 6% 27%	1610
	11th to 20th	Day	7% 11% 4 9% 8% 5% 6% 6% 6% 8% 29%	1600
	21st to end	Day	9% 12% 4 12% 8% 8% 7% 6% 6% 7% 21%	1472
December	1st to 10th	Day	5% 12% 5% 10% 7% 8% 6% 5% 7% 8% 28%	2290
	11th to 20th	Day	5% 13% 7% 16% 9% 7% 6% 5% 7% 8% 18%	2361
	21st to end	Day	4 13% 5% 13% 8% 9% 8% 7% 8% 8% 17%	3084
January	1st to 10th	Night	9% 18% 6% 13% 8% 7% 6% 5% 7% 7% 15%	6766
	11th to 20th	Night	5% 12% 5% 11% 7% 6% 5% 4 6% 9% 29%	6535
	21st to end	Night	5% 13% 5% 12% 8% 7% 7% 5% 6% 7% 27%	6952
February	1st to 10th	Night	8% 15% 6% 13% 8% 7% 6% 5% 6% 7% 20%	2747
	11th to 20th	Night	6% 13% 4 10% 6% 6% 6% 5% 5% 7% 33%	2532
	21st to end	Night	4 12% 5% 13% 8% 5% 7% 6% 7% 7% 26%	2044
March	1st to 10th	Night	2 10% 4 8% 5% 6% 7% 6% 8% 10% 34%	5376
	11th to 20th	Night	2 7% 3 9% 6% 6% 7% 5% 8% 9% 39%	5158
	21st to end	Night	6% 10% 4 9% 7% 7% 7% 5% 8% 9% 27%	5121
April	1st to 10th	Night	5% 10% 3 9% 6% 6% 6% 5% 6% 8% 35%	2000
	11th to 20th	Night	4 10% 4 9% 6% 6% 6% 4 8% 8% 33%	1969
	21st to end	Night	6% 8% 3 7% 6% 6% 6% 5% 6% 8% 40%	1600
May	1st to 10th	Night	8% 9% 3 8% 6% 5% 5% 4 5% 6% 41%	3640
	11th to 20th	Night	8% 9% 3 8% 5% 6% 6% 4 7% 10% 33%	3616
	21st to end	Night	9% 8% 3 8% 5% 5% 5% 5% 6% 8% 38%	3886
June	1st to 10th	Night	12% 6% 2 9% 5% 4 6% 5% 7% 9% 35%	1219
	11th to 20th	Night	12% 7% 3 8% 6% 6% 6% 6% 7% 8% 31%	1200
	21st to end	Night	6% 5% 2 8% 6% 7% 6% 4 6% 8% 43%	1200
July	1st to 10th	Night	7% 5% 2 5% 4 4 4 3 5% 7% 53%	3028
	11th to 20th	Night	5% 3 2 4 3 3 4 3 5% 8% 61%	3244
	21st to end	Night	3 3 2 5% 4 4 5% 4 7% 8% 55%	3969
August	1st to 10th	Night	2 3 1 5% 4 5% 5% 6% 7% 9% 53%	2609
	11th to 20th	Night	3 3 2 7% 5% 5% 6% 5% 8% 9% 47%	2625
	21st to end	Night	9% 5% 2 5% 4 4 4 4 7% 8% 48%	3476
September	1st to 10th	Night	5% 4 1 6% 4 4 3 4 6% 6% 56%	1930
	11th to 20th	Night	7% 5% 2 6% 5% 4 4 3 6% 9% 48%	1900
	21st to end	Night	8% 7% 3 7% 4 5% 4 4 6% 8% 44%	2138
October	1st to 10th	Night	9% 7% 2 7% 6% 5% 5% 4 6% 8% 42%	3800
	11th to 20th	Night	8% 9% 4 8% 5% 4 5% 4 6% 8% 38%	3852
	21st to end	Night	7% 9% 4 10% 6% 5% 4 3 5% 8% 39%	4457
November	1st to 10th	Night	12% 13% 3 9% 8% 7% 7% 5% 5% 6% 26%	2687
	11th to 20th	Night	8% 13% 5% 11% 8% 7% 7% 4 6% 6% 26%	2800
	21st to end	Night	8% 16% 4 11% 9% 7% 7% 5% 6% 6% 20%	2905
December	1st to 10th	Night	5% 9% 4 9% 7% 6% 6% 5% 8% 10% 30%	4890
	11th to 20th	Night	8% 16% 6% 15% 8% 8% 7% 4 5% 6% 16%	5826
	21st to end	Night	5% 13% 4 12% 8% 8% 8% 5% 7% 8% 21%	7902

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	60% 15% 14% 9% 1	3179
	11th to 20th	Day	44% 12% 19% 15% 5% 4	3382
	21st to end	Day	50% 16% 20% 13% 1	4004
February	1st to 10th	Day	58% 10% 12% 11% 8% 1	1650
	11th to 20th	Day	51% 11% 17% 13% 7%	1764
	21st to end	Day	52% 14% 17% 12% 4 1	1585
March	1st to 10th	Day	40% 14% 21% 17% 7%	4518
	11th to 20th	Day	40% 11% 18% 27% 5%	4839
	21st to end	Day	50% 12% 16% 14% 8%	5854
April	1st to 10th	Day	51% 16% 15% 15% 4	2400
	11th to 20th	Day	49% 12% 14% 16% 8% 2	2378
	21st to end	Day	48% 12% 16% 16% 8%	2800
May	1st to 10th	Day	35% 9% 12% 27% 15% 2	6320
	11th to 20th	Day	42% 13% 20% 20% 5%	6280
	21st to end	Day	44% 12% 16% 24% 4 1	6986
June	1st to 10th	Day	46% 12% 14% 15% 9% 4	3178
	11th to 20th	Day	52% 12% 14% 15% 6%	3200
	21st to end	Day	40% 10% 18% 20% 11% 2	3200
July	1st to 10th	Day	23% 7% 15% 25% 21% 10%	6854
	11th to 20th	Day	21% 7% 16% 26% 21% 8%	6621
	21st to end	Day	20% 7% 24% 29% 16% 5%	6681
August	1st to 10th	Day	19% 8% 14% 35% 22% 2	4524
	11th to 20th	Day	24% 10% 27% 29% 10% 2	4463
	21st to end	Day	30% 9% 23% 29% 8% 1	4439
September	1st to 10th	Day	30% 10% 16% 30% 12% 2	2317
	11th to 20th	Day	40% 10% 13% 24% 12% 2	2280
	21st to end	Day	42% 11% 20% 18% 9% 1	2039
October	1st to 10th	Day	38% 10% 23% 22% 7%	3180
	11th to 20th	Day	46% 9% 20% 21% 4	3082
	21st to end	Day	44% 12% 25% 17% 3	3101
November	1st to 10th	Day	56% 12% 13% 14% 4 1	1610
	11th to 20th	Day	51% 14% 15% 14% 4 1	1600
	21st to end	Day	58% 14% 13% 11% 3	1472
December	1st to 10th	Day	53% 14% 22% 10% 1	2290
	11th to 20th	Day	58% 17% 13% 10% 3	2363
	21st to end	Day	56% 16% 17% 10% 2	3084
January	1st to 10th	Night	59% 17% 15% 7% 2	6766
	11th to 20th	Night	48% 12% 18% 13% 6% 3	6575
	21st to end	Night	51% 15% 20% 12% 1	6952
February	1st to 10th	Night	60% 10% 11% 11% 7% 1	2747
	11th to 20th	Night	49% 11% 15% 17% 7% 1	2534
	21st to end	Night	52% 12% 17% 13% 6%	2044
March	1st to 10th	Night	38% 14% 21% 20% 7%	5376
	11th to 20th	Night	35% 11% 21% 24% 9%	5159
	21st to end	Night	48% 14% 15% 14% 9%	5121
April	1st to 10th	Night	44% 14% 20% 17% 5%	2000
	11th to 20th	Night	44% 12% 17% 17% 10%	1969
	21st to end	Night	38% 13% 17% 22% 10%	1600
May	1st to 10th	Night	40% 9% 11% 25% 15% 1	3637
	11th to 20th	Night	39% 12% 19% 23% 6%	3616
	21st to end	Night	38% 12% 20% 24% 5% 1	3886
June	1st to 10th	Night	43% 10% 15% 20% 9% 3	1219
	11th to 20th	Night	46% 11% 17% 18% 8%	1200
	21st to end	Night	37% 10% 20% 19% 12% 2	1200
July	1st to 10th	Night	30% 6% 14% 22% 21% 7%	2993
	11th to 20th	Night	22% 7% 16% 27% 23% 5%	3202
	21st to end	Night	24% 8% 19% 27% 14% 8%	3857
August	1st to 10th	Night	23% 8% 14% 32% 20% 3	2601
	11th to 20th	Night	28% 11% 23% 25% 12% 2	2649
	21st to end	Night	31% 9% 25% 23% 10% 1	3476
September	1st to 10th	Night	27% 9% 16% 30% 15% 2	1930
	11th to 20th	Night	33% 10% 17% 22% 15% 4	1900
	21st to end	Night	37% 12% 19% 18% 12% 2	2138
October	1st to 10th	Night	39% 9% 21% 23% 8%	3800
	11th to 20th	Night	43% 8% 19% 24% 6%	3852
	21st to end	Night	44% 7% 22% 23% 3	4457
November	1st to 10th	Night	56% 13% 13% 13% 5% 1	2687
	11th to 20th	Night	55% 12% 14% 12% 6% 1	2800
	21st to end	Night	60% 12% 15% 9% 4	2905
December	1st to 10th	Night	46% 16% 26% 11% 2	4890
	11th to 20th	Night	66% 11% 14% 7% 2	5823
	21st to end	Night	53% 15% 19% 11% 3	7902

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	15% 21% 27% 23% 8% 7%	200
	11th to 20th	Day	11% 15% 32% 28% 12% 3	200
	21st to end	Day	15% 19% 32% 21% 10% 3	220
February	1st to 10th	Day	13% 22% 38% 16% 8% 3	250
	11th to 20th	Day	12% 22% 29% 25% 10% 1	395
	21st to end	Day	10% 22% 33% 24% 9% 2	381
March	1st to 10th	Day	16% 22% 31% 20% 11%	500
	11th to 20th	Day	15% 23% 27% 21% 13% 2	500
	21st to end	Day	17% 24% 30% 15% 12% 2	550
April	1st to 10th	Day	18% 24% 28% 21% 8% 1	500
	11th to 20th	Day	17% 23% 27% 22% 9% 2	492
	21st to end	Day	13% 20% 33% 19% 11% 3	500
May	1st to 10th	Day	14% 22% 28% 28% 7% 2	503
	11th to 20th	Day	13% 12% 27% 30% 16% 3	528
	21st to end	Day	11% 13% 32% 26% 15% 3	603
June	1st to 10th	Day	16% 17% 31% 23% 11% 1	908
	11th to 20th	Day	17% 12% 29% 28% 11% 4	930
	21st to end	Day	11% 11% 24% 29% 21% 3	930
July	1st to 10th	Day	9% 10% 26% 32% 19% 3	791
	11th to 20th	Day	7% 13% 26% 32% 18% 4	692
	21st to end	Day	5% 7% 21% 37% 21% 9%	575
August	1st to 10th	Day	5% 8% 21% 34% 24% 9%	527
	11th to 20th	Day	8% 9% 23% 30% 21% 9%	517
	21st to end	Day	9% 12% 25% 27% 16% 11%	583
September	1st to 10th	Day	11% 13% 29% 24% 16% 7%	503
	11th to 20th	Day	13% 14% 24% 28% 16% 4	490
	21st to end	Day	15% 19% 28% 25% 11% 2	490
October	1st to 10th	Day	18% 15% 23% 24% 15% 4	490
	11th to 20th	Day	19% 20% 24% 21% 14% 2	449
	21st to end	Day	20% 19% 27% 22% 10% 2	330
November	1st to 10th	Day	18% 18% 34% 18% 10% 1	222
	11th to 20th	Day	19% 22% 27% 17% 13% 3	200
	21st to end	Day	16% 18% 29% 23% 10% 6%	200
December	1st to 10th	Day	11% 17% 18% 26% 22% 7%	200
	11th to 20th	Day	17% 14% 34% 21% 12% 4	200
	21st to end	Day	12% 14% 30% 30% 12% 2	220
January	1st to 10th	Night	21% 14% 31% 23% 9% 1	900
	11th to 20th	Night	15% 11% 31% 31% 12% 1	855
	21st to end	Night	11% 12% 32% 30% 13% 2	880
February	1st to 10th	Night	17% 14% 32% 26% 9% 3	800
	11th to 20th	Night	11% 12% 29% 37% 11% 1	784
	21st to end	Night	11% 13% 29% 28% 17% 2	660
March	1st to 10th	Night	11% 15% 29% 29% 14% 2	800
	11th to 20th	Night	10% 16% 31% 28% 14% 1	800
	21st to end	Night	11% 15% 28% 28% 15% 3	880
April	1st to 10th	Night	11% 14% 27% 30% 16% 3	800
	11th to 20th	Night	10% 15% 31% 30% 14% 1	781
	21st to end	Night	9% 14% 31% 30% 14% 2	400
May	1st to 10th	Night	12% 10% 29% 31% 16% 2	400
	11th to 20th	Night	10% 6% 25% 39% 18% 2	394
	21st to end	Night	11% 9% 21% 36% 21% 2	433
June	1st to 10th	Night	14% 9% 30% 36% 11% 1	400
	11th to 20th	Night	13% 7% 30% 33% 16% 2	400
	21st to end	Night	8% 7% 24% 36% 22% 2	400
July	1st to 10th	Night	9% 5% 22% 41% 22% 1	390
	11th to 20th	Night	6% 7% 22% 37% 27% 1	388
	21st to end	Night	5% 3 17% 43% 29% 3	438
August	1st to 10th	Night	5% 3 17% 36% 34% 6%	398
	11th to 20th	Night	6% 2 18% 36% 32% 6%	418
	21st to end	Night	9% 6% 20% 35% 28% 3	800
September	1st to 10th	Night	7% 9% 19% 35% 27% 3	772
	11th to 20th	Night	10% 6% 18% 29% 31% 6%	760
	21st to end	Night	14% 11% 24% 30% 18% 3	760
October	1st to 10th	Night	13% 9% 22% 34% 20% 2	760
	11th to 20th	Night	16% 11% 25% 28% 18% 2	760
	21st to end	Night	19% 14% 27% 26% 12% 2	836
November	1st to 10th	Night	20% 14% 28% 31% 6% 1	780
	11th to 20th	Night	18% 18% 25% 26% 11% 1	800
	21st to end	Night	19% 13% 29% 26% 10% 3	905
December	1st to 10th	Night	13% 12% 27% 32% 14% 2	1000
	11th to 20th	Night	18% 15% 30% 28% 9% 1	1067
	21st to end	Night	18% 13% 33% 28% 8% 1	1187

Page generated at 2025-08-31 22:51:07. Version ac07

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