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 2024-03-28.

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	8% 8% 4 8% 7% 4 6% 6% 6% 8% 34%	78209
	Night	7% 10% 5% 9% 8% 5% 6% 6% 6% 7% 31%	81727
Transparency	Day	46% 12% 16% 17% 8% 1	77922
	Night	48% 12% 16% 15% 7% 1	81594
Seeing	Day	14% 17% 29% 25% 13% 3	14731
	Night	13% 12% 27% 30% 16% 2	23314

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	8% 17% 7% 11% 9% 5% 7% 7% 6% 6% 17%	2219
	11th to 20th	Day	9% 14% 4 9% 10% 5% 6% 5% 6% 7% 25%	2330
	21st to end	Day	8% 15% 7% 12% 9% 6% 7% 6% 6% 6% 17%	2794
February	1st to 10th	Day	9% 13% 6% 11% 8% 5% 6% 6% 6% 7% 24%	1567
	11th to 20th	Day	5% 12% 5% 9% 6% 5% 7% 7% 7% 8% 29%	1665
	21st to end	Day	4 10% 6% 11% 8% 6% 7% 6% 7% 8% 26%	1508
March	1st to 10th	Day	4 9% 5% 9% 8% 5% 7% 8% 6% 10% 27%	1900
	11th to 20th	Day	4 9% 5% 8% 8% 5% 7% 7% 8% 8% 31%	2017
	21st to end	Day	6% 10% 5% 9% 9% 5% 7% 8% 7% 8% 26%	2409
April	1st to 10th	Day	5% 12% 6% 9% 7% 5% 8% 8% 7% 10% 24%	2160
	11th to 20th	Day	6% 10% 5% 10% 8% 5% 6% 6% 6% 9% 28%	2136
	21st to end	Day	7% 9% 4 8% 9% 5% 7% 6% 8% 8% 30%	2520
May	1st to 10th	Day	9% 9% 4 8% 8% 5% 7% 6% 5% 8% 33%	2520
	11th to 20th	Day	8% 7% 2 7% 7% 4 6% 6% 8% 10% 34%	2477
	21st to end	Day	11% 9% 4 8% 7% 4 6% 6% 6% 7% 32%	2749
June	1st to 10th	Day	14% 7% 4 6% 6% 4 6% 6% 7% 8% 31%	2860
	11th to 20th	Day	14% 8% 4 7% 8% 5% 7% 7% 7% 7% 25%	2880
	21st to end	Day	8% 5% 2 7% 8% 4 6% 6% 6% 9% 40%	2880
July	1st to 10th	Day	6% 4 2 5% 5% 3 6% 6% 7% 7% 49%	2764
	11th to 20th	Day	5% 3 2 4 5% 4 6% 6% 8% 8% 52%	2678
	21st to end	Day	4 2 1 3 3 2 4 5% 6% 8% 61%	2741
August	1st to 10th	Day	4 3 2 4 5% 3 4 5% 6% 8% 56%	2507
	11th to 20th	Day	4 3 1 4 4 2 5% 5% 5% 9% 58%	2453
	21st to end	Day	7% 4 2 5% 5% 3 5% 6% 7% 9% 46%	2448
September	1st to 10th	Day	6% 4 2 5% 6% 3 4 4 5% 8% 52%	2160
	11th to 20th	Day	10% 7% 3 5% 7% 3 5% 4 5% 8% 43%	2160
	21st to end	Day	11% 7% 2 6% 6% 5% 5% 5% 8% 8% 38%	1933
October	1st to 10th	Day	9% 7% 3 7% 8% 5% 5% 5% 5% 8% 39%	1800
	11th to 20th	Day	8% 8% 3 7% 7% 5% 6% 6% 7% 8% 35%	1762
	21st to end	Day	10% 11% 4 7% 7% 4 4 6% 6% 7% 34%	1782
November	1st to 10th	Day	10% 12% 4 9% 9% 5% 6% 6% 4 6% 28%	1528
	11th to 20th	Day	8% 10% 6% 8% 8% 4 6% 7% 6% 8% 30%	1520
	21st to end	Day	9% 10% 5% 10% 9% 7% 8% 8% 6% 7% 21%	1399
December	1st to 10th	Day	6% 12% 5% 12% 10% 6% 8% 6% 6% 5% 23%	1330
	11th to 20th	Day	5% 12% 7% 15% 12% 5% 7% 7% 6% 6% 18%	1499
	21st to end	Day	6% 11% 5% 11% 10% 6% 9% 8% 8% 8% 18%	2154
January	1st to 10th	Night	11% 17% 7% 12% 10% 6% 7% 5% 5% 6% 14%	4726
	11th to 20th	Night	7% 14% 7% 12% 10% 5% 6% 6% 6% 7% 20%	4565
	21st to end	Night	6% 14% 7% 13% 10% 6% 8% 7% 6% 6% 17%	4862
February	1st to 10th	Night	8% 15% 7% 11% 9% 5% 7% 6% 6% 7% 20%	2610
	11th to 20th	Night	6% 12% 4 9% 8% 5% 6% 6% 5% 6% 33%	2402
	21st to end	Night	5% 11% 6% 12% 9% 4 7% 7% 6% 7% 26%	1945
March	1st to 10th	Night	4 10% 4 7% 7% 5% 8% 7% 6% 7% 34%	2280
	11th to 20th	Night	3 9% 4 7% 7% 4 7% 6% 8% 8% 36%	2160
	21st to end	Night	5% 9% 4 8% 9% 6% 7% 7% 7% 8% 30%	2102
April	1st to 10th	Night	5% 8% 4 8% 7% 4 7% 7% 6% 8% 36%	1800
	11th to 20th	Night	5% 10% 5% 8% 8% 5% 7% 6% 8% 9% 32%	1772
	21st to end	Night	6% 7% 3 6% 6% 5% 6% 6% 6% 8% 40%	1440
May	1st to 10th	Night	9% 8% 5% 9% 7% 4 6% 5% 6% 7% 35%	1440
	11th to 20th	Night	7% 6% 3 6% 6% 4 7% 6% 7% 9% 37%	1416
	21st to end	Night	12% 6% 4 6% 7% 3 5% 6% 7% 10% 35%	1522
June	1st to 10th	Night	13% 5% 3 8% 6% 3 6% 5% 6% 10% 33%	1098
	11th to 20th	Night	13% 6% 4 8% 7% 4 7% 7% 7% 8% 29%	1080
	21st to end	Night	5% 4 3 6% 7% 6% 7% 5% 6% 8% 44%	1080
July	1st to 10th	Night	7% 4 2 4 6% 3 6% 6% 7% 9% 46%	1192
	11th to 20th	Night	5% 3 2 4 5% 3 6% 5% 6% 9% 52%	1282
	21st to end	Night	4 2 1 4 4 3 3 5% 6% 9% 60%	1576
August	1st to 10th	Night	3 3 2 4 5% 2 4 5% 5% 7% 60%	1432
	11th to 20th	Night	3 3 1 4 4 3 4 5% 6% 8% 58%	1443
	21st to end	Night	6% 5% 2 5% 5% 3 6% 6% 8% 8% 47%	1908
September	1st to 10th	Night	5% 4 2 5% 5% 3 4 5% 7% 7% 54%	1800
	11th to 20th	Night	8% 4 3 5% 6% 4 4 4 6% 9% 48%	1800
	21st to end	Night	8% 7% 3 6% 5% 4 4 5% 5% 8% 44%	2025
October	1st to 10th	Night	8% 6% 3 5% 6% 4 6% 7% 6% 8% 43%	2160
	11th to 20th	Night	9% 9% 4 7% 5% 4 5% 5% 5% 7% 39%	2197
	21st to end	Night	9% 9% 3 8% 7% 4 4 5% 6% 6% 38%	2574
November	1st to 10th	Night	13% 12% 3 8% 8% 6% 7% 6% 5% 6% 26%	2549
	11th to 20th	Night	9% 11% 6% 9% 9% 5% 7% 5% 5% 7% 26%	2660
	21st to end	Night	9% 13% 7% 9% 10% 5% 8% 7% 6% 6% 21%	2759
December	1st to 10th	Night	8% 11% 6% 9% 10% 5% 7% 7% 6% 8% 23%	2850
	11th to 20th	Night	10% 16% 7% 14% 9% 5% 8% 5% 5% 5% 15%	3688
	21st to end	Night	6% 13% 5% 9% 10% 7% 9% 7% 6% 7% 20%	5532

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	62% 15% 13% 8% 2	2219
	11th to 20th	Day	55% 11% 16% 10% 2 6%	2352
	21st to end	Day	60% 17% 14% 7% 2	2794
February	1st to 10th	Day	60% 11% 12% 11% 6% 1	1567
	11th to 20th	Day	51% 11% 17% 13% 7%	1674
	21st to end	Day	52% 14% 17% 12% 4 1	1508
March	1st to 10th	Day	50% 14% 16% 13% 6%	1900
	11th to 20th	Day	48% 14% 17% 17% 4	2017
	21st to end	Day	52% 14% 18% 12% 3	2409
April	1st to 10th	Day	52% 16% 15% 13% 4	2160
	11th to 20th	Day	51% 12% 13% 15% 8% 1	2136
	21st to end	Day	49% 13% 17% 15% 7%	2520
May	1st to 10th	Day	50% 11% 16% 15% 8% 1	2520
	11th to 20th	Day	41% 14% 19% 19% 7%	2480
	21st to end	Day	49% 12% 15% 17% 5% 1	2750
June	1st to 10th	Day	49% 12% 14% 14% 7% 4	2860
	11th to 20th	Day	55% 13% 14% 14% 5%	2880
	21st to end	Day	40% 11% 17% 19% 11% 2	2880
July	1st to 10th	Day	32% 9% 17% 22% 15% 4	2690
	11th to 20th	Day	28% 11% 17% 27% 15% 2	2597
	21st to end	Day	20% 8% 17% 31% 21% 4	2589
August	1st to 10th	Day	25% 10% 18% 26% 18% 3	2490
	11th to 20th	Day	23% 10% 19% 29% 16% 3	2453
	21st to end	Day	33% 11% 19% 26% 10% 2	2448
September	1st to 10th	Day	31% 10% 17% 29% 11% 2	2160
	11th to 20th	Day	40% 10% 13% 23% 12% 2	2160
	21st to end	Day	42% 12% 19% 18% 8% 1	1933
October	1st to 10th	Day	43% 12% 17% 23% 5%	1800
	11th to 20th	Day	44% 13% 19% 19% 4	1762
	21st to end	Day	49% 11% 17% 18% 5%	1782
November	1st to 10th	Day	57% 12% 13% 14% 5% 1	1528
	11th to 20th	Day	51% 14% 16% 14% 4 1	1520
	21st to end	Day	58% 14% 13% 11% 4	1399
December	1st to 10th	Day	61% 13% 13% 11% 2	1330
	11th to 20th	Day	58% 19% 13% 8% 3	1501
	21st to end	Day	54% 17% 17% 10% 2	2154
January	1st to 10th	Night	62% 15% 15% 7% 2	4726
	11th to 20th	Night	59% 10% 13% 9% 4 4	4605
	21st to end	Night	58% 17% 15% 7% 2	4862
February	1st to 10th	Night	61% 10% 11% 11% 6% 1	2610
	11th to 20th	Night	49% 11% 15% 17% 8% 1	2404
	21st to end	Night	52% 12% 17% 13% 6%	1945
March	1st to 10th	Night	47% 14% 16% 15% 8% 1	2280
	11th to 20th	Night	41% 13% 20% 20% 6%	2161
	21st to end	Night	49% 15% 16% 15% 5%	2102
April	1st to 10th	Night	43% 14% 20% 17% 6%	1800
	11th to 20th	Night	46% 12% 17% 15% 10%	1772
	21st to end	Night	39% 12% 16% 21% 10%	1440
May	1st to 10th	Night	47% 10% 16% 16% 10% 1	1440
	11th to 20th	Night	40% 12% 20% 19% 9%	1416
	21st to end	Night	44% 11% 19% 17% 9%	1522
June	1st to 10th	Night	45% 11% 15% 19% 7% 4	1098
	11th to 20th	Night	48% 12% 17% 18% 6%	1080
	21st to end	Night	36% 10% 19% 20% 12% 2	1080
July	1st to 10th	Night	33% 9% 18% 20% 15% 4	1157
	11th to 20th	Night	26% 9% 18% 29% 17% 1	1240
	21st to end	Night	19% 9% 17% 26% 23% 6%	1488
August	1st to 10th	Night	21% 8% 19% 24% 23% 4	1424
	11th to 20th	Night	22% 9% 18% 28% 20% 3	1443
	21st to end	Night	32% 11% 18% 24% 14% 2	1908
September	1st to 10th	Night	29% 10% 17% 29% 14% 2	1800
	11th to 20th	Night	33% 10% 16% 22% 15% 4	1800
	21st to end	Night	37% 12% 19% 18% 13% 2	2025
October	1st to 10th	Night	37% 12% 17% 26% 9%	2160
	11th to 20th	Night	44% 10% 16% 22% 8%	2197
	21st to end	Night	46% 9% 19% 20% 5%	2574
November	1st to 10th	Night	56% 12% 13% 13% 5%	2549
	11th to 20th	Night	55% 12% 14% 12% 6% 1	2660
	21st to end	Night	60% 12% 15% 9% 4	2759
December	1st to 10th	Night	56% 11% 17% 12% 4	2850
	11th to 20th	Night	68% 11% 11% 7% 2	3685
	21st to end	Night	54% 15% 19% 10% 3	5532

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	16% 22% 27% 21% 6% 7%	180
	11th to 20th	Day	12% 17% 32% 25% 11% 3	180
	21st to end	Day	16% 20% 33% 20% 10% 2	198
February	1st to 10th	Day	14% 24% 40% 16% 6%	227
	11th to 20th	Day	13% 23% 30% 23% 10% 1	365
	21st to end	Day	10% 22% 33% 23% 9% 2	352
March	1st to 10th	Day	16% 24% 31% 19% 10%	460
	11th to 20th	Day	15% 23% 27% 21% 12% 2	460
	21st to end	Day	18% 24% 31% 14% 11% 2	491
April	1st to 10th	Day	20% 23% 28% 21% 8% 1	420
	11th to 20th	Day	18% 25% 25% 19% 10% 2	412
	21st to end	Day	14% 21% 36% 18% 9% 2	420
May	1st to 10th	Day	14% 22% 28% 28% 6% 2	423
	11th to 20th	Day	12% 12% 28% 29% 16% 3	448
	21st to end	Day	13% 12% 32% 25% 16% 3	511
June	1st to 10th	Day	17% 19% 31% 21% 10% 1	790
	11th to 20th	Day	18% 12% 31% 27% 10% 2	810
	21st to end	Day	12% 11% 26% 29% 19% 3	810
July	1st to 10th	Day	10% 11% 28% 32% 17% 2	685
	11th to 20th	Day	7% 15% 27% 32% 16% 3	596
	21st to end	Day	6% 7% 23% 39% 19% 6%	487
August	1st to 10th	Day	5% 9% 22% 34% 23% 7%	447
	11th to 20th	Day	8% 9% 23% 32% 21% 5%	437
	21st to end	Day	9% 13% 28% 29% 14% 6%	495
September	1st to 10th	Day	12% 14% 31% 26% 13% 4	450
	11th to 20th	Day	14% 15% 24% 28% 16% 3	450
	21st to end	Day	16% 18% 29% 24% 12% 2	450
October	1st to 10th	Day	19% 15% 23% 23% 16% 4	450
	11th to 20th	Day	18% 21% 25% 21% 14% 2	412
	21st to end	Day	22% 19% 29% 19% 10% 1	297
November	1st to 10th	Day	20% 19% 33% 18% 11% 1	200
	11th to 20th	Day	18% 23% 25% 17% 13% 3	180
	21st to end	Day	17% 19% 30% 20% 9% 5%	180
December	1st to 10th	Day	11% 18% 19% 27% 20% 4	180
	11th to 20th	Day	17% 16% 34% 18% 12% 4	180
	21st to end	Day	12% 15% 32% 28% 11% 2	198
January	1st to 10th	Night	21% 15% 32% 21% 9% 1	850
	11th to 20th	Night	16% 11% 31% 30% 12% 1	810
	21st to end	Night	11% 12% 32% 29% 13% 2	836
February	1st to 10th	Night	18% 14% 32% 26% 8% 2	760
	11th to 20th	Night	11% 12% 30% 36% 11%	744
	21st to end	Night	12% 13% 29% 28% 17% 2	628
March	1st to 10th	Night	11% 16% 29% 27% 14% 2	760
	11th to 20th	Night	10% 16% 31% 28% 14% 1	760
	21st to end	Night	11% 16% 28% 27% 14% 3	820
April	1st to 10th	Night	11% 13% 28% 29% 17% 3	720
	11th to 20th	Night	10% 15% 30% 29% 15% 1	704
	21st to end	Night	9% 14% 31% 30% 13% 2	360
May	1st to 10th	Night	12% 10% 29% 31% 16% 2	360
	11th to 20th	Night	10% 6% 25% 40% 18% 2	354
	21st to end	Night	12% 8% 20% 35% 22% 2	389
June	1st to 10th	Night	14% 8% 30% 34% 12% 1	360
	11th to 20th	Night	14% 7% 31% 32% 14% 2	360
	21st to end	Night	8% 7% 26% 35% 21% 3	360
July	1st to 10th	Night	9% 5% 23% 41% 21% 1	350
	11th to 20th	Night	7% 7% 24% 37% 24% 1	348
	21st to end	Night	5% 4 18% 44% 27% 3	394
August	1st to 10th	Night	4 3 18% 35% 34% 6%	358
	11th to 20th	Night	6% 2 18% 37% 31% 6%	375
	21st to end	Night	8% 7% 22% 35% 26% 3	720
September	1st to 10th	Night	8% 10% 20% 34% 25% 3	720
	11th to 20th	Night	10% 7% 18% 29% 30% 6%	720
	21st to end	Night	14% 11% 24% 29% 19% 3	720
October	1st to 10th	Night	13% 9% 21% 33% 21% 3	720
	11th to 20th	Night	17% 11% 25% 27% 18% 2	720
	21st to end	Night	19% 14% 28% 25% 12% 2	792
November	1st to 10th	Night	21% 14% 28% 30% 6% 1	740
	11th to 20th	Night	19% 18% 26% 26% 11% 1	760
	21st to end	Night	19% 14% 30% 25% 10% 2	859
December	1st to 10th	Night	13% 12% 28% 31% 14% 2	950
	11th to 20th	Night	18% 15% 31% 28% 8%	1010
	21st to end	Night	18% 13% 32% 28% 8% 1	1123

Page generated at 2024-03-24 20:37:03. Version ac07

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